From d0b22e1d856cf8f78e152dfb6c150e001e03dd52 Mon Sep 17 00:00:00 2001 From: Gerald Kunzmann Date: Tue, 14 Feb 2017 15:38:29 +0000 Subject: Update docs structure according to new guidelines in https://wiki.opnfv.org/display/DOC Change-Id: I1c8c20cf85aa46269c5bc369f17ab0020862ddc5 Signed-off-by: Gerald Kunzmann --- docs/development/requirements/01-intro.rst | 51 + docs/development/requirements/02-use_cases.rst | 195 ++++ docs/development/requirements/03-architecture.rst | 340 +++++++ docs/development/requirements/04-gaps.rst | 389 ++++++++ .../development/requirements/05-implementation.rst | 1050 ++++++++++++++++++++ docs/development/requirements/06-summary.rst | 24 + docs/development/requirements/07-annex.rst | 129 +++ docs/development/requirements/99-references.rst | 32 + docs/development/requirements/glossary.rst | 89 ++ docs/development/requirements/images/LICENSE | 14 + docs/development/requirements/images/figure1.png | Bin 0 -> 79420 bytes docs/development/requirements/images/figure10.png | Bin 0 -> 422212 bytes docs/development/requirements/images/figure11.png | Bin 0 -> 355225 bytes docs/development/requirements/images/figure12.png | Bin 0 -> 2144916 bytes docs/development/requirements/images/figure13.png | Bin 0 -> 646427 bytes docs/development/requirements/images/figure14.png | Bin 0 -> 578986 bytes docs/development/requirements/images/figure2.png | Bin 0 -> 82010 bytes docs/development/requirements/images/figure3.png | Bin 0 -> 308234 bytes docs/development/requirements/images/figure4.png | Bin 0 -> 186805 bytes docs/development/requirements/images/figure5a.png | Bin 0 -> 43787 bytes docs/development/requirements/images/figure5b.png | Bin 0 -> 45067 bytes docs/development/requirements/images/figure5c.png | Bin 0 -> 44400 bytes docs/development/requirements/images/figure6.png | Bin 0 -> 425612 bytes docs/development/requirements/images/figure7.png | Bin 0 -> 315053 bytes docs/development/requirements/images/figure8.png | Bin 0 -> 464430 bytes docs/development/requirements/images/figure9.png | Bin 0 -> 459353 bytes docs/development/requirements/index.rst | 62 ++ 27 files changed, 2375 insertions(+) create mode 100644 docs/development/requirements/01-intro.rst create mode 100644 docs/development/requirements/02-use_cases.rst create mode 100644 docs/development/requirements/03-architecture.rst create mode 100644 docs/development/requirements/04-gaps.rst create mode 100644 docs/development/requirements/05-implementation.rst create mode 100644 docs/development/requirements/06-summary.rst create mode 100644 docs/development/requirements/07-annex.rst create mode 100644 docs/development/requirements/99-references.rst create mode 100644 docs/development/requirements/glossary.rst create mode 100644 docs/development/requirements/images/LICENSE create mode 100644 docs/development/requirements/images/figure1.png create mode 100755 docs/development/requirements/images/figure10.png create mode 100755 docs/development/requirements/images/figure11.png create mode 100755 docs/development/requirements/images/figure12.png create mode 100755 docs/development/requirements/images/figure13.png create mode 100755 docs/development/requirements/images/figure14.png create mode 100644 docs/development/requirements/images/figure2.png create mode 100755 docs/development/requirements/images/figure3.png create mode 100755 docs/development/requirements/images/figure4.png create mode 100755 docs/development/requirements/images/figure5a.png create mode 100755 docs/development/requirements/images/figure5b.png create mode 100755 docs/development/requirements/images/figure5c.png create mode 100755 docs/development/requirements/images/figure6.png create mode 100755 docs/development/requirements/images/figure7.png create mode 100755 docs/development/requirements/images/figure8.png create mode 100755 docs/development/requirements/images/figure9.png create mode 100644 docs/development/requirements/index.rst (limited to 'docs/development/requirements') diff --git a/docs/development/requirements/01-intro.rst b/docs/development/requirements/01-intro.rst new file mode 100644 index 00000000..ed666cd1 --- /dev/null +++ b/docs/development/requirements/01-intro.rst @@ -0,0 +1,51 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +Introduction +============ + +The goal of this project is to build an NFVI fault management and maintenance +framework supporting high availability of the Network Services on top of the +virtualized infrastructure. The key feature is immediate notification of +unavailability of virtualized resources from VIM, to support failure recovery, +or failure avoidance of VNFs running on them. Requirement survey and development +of missing features in NFVI and VIM are in scope of this project in order to +fulfil requirements for fault management and maintenance in NFV. + +The purpose of this requirement project is to clarify the necessary features of +NFVI fault management, and maintenance, identify missing features in the current +OpenSource implementations, provide a potential implementation architecture and +plan, provide implementation guidelines in relevant upstream projects to realize +those missing features, and define the VIM northbound interfaces necessary to +perform the task of NFVI fault management, and maintenance in alignment with +ETSI NFV [ENFV]_. + +Problem description +------------------- + +A Virtualized Infrastructure Manager (VIM), e.g. OpenStack [OPSK]_, cannot +detect certain Network Functions Virtualization Infrastructure (NFVI) faults. +This feature is necessary to detect the faults and notify the Consumer in order +to ensure the proper functioning of EPC VNFs like MME and S/P-GW. + +* EPC VNFs are often in active standby (ACT-STBY) configuration and need to + switch from STBY mode to ACT mode as soon as relevant faults are detected in + the active (ACT) VNF. + +* NFVI encompasses all elements building up the environment in which VNFs are + deployed, e.g., Physical Machines, Hypervisors, Storage, and Network elements. + +In addition, VIM, e.g. OpenStack, needs to receive maintenance instructions from +the Consumer, i.e. the operator/administrator of the VNF. + +* Change the state of certain Physical Machines (PMs), e.g. empty the PM, so + that maintenance work can be performed at these machines. + +Note: Although fault management and maintenance are different operations in NFV, +both are considered as part of this project as -- except for the trigger -- they +share a very similar work and message flow. Hence, from implementation +perspective, these two are kept together in the Doctor project because of this +high degree of similarity. + +.. + vim: set tabstop=4 expandtab textwidth=80: diff --git a/docs/development/requirements/02-use_cases.rst b/docs/development/requirements/02-use_cases.rst new file mode 100644 index 00000000..0a1f6413 --- /dev/null +++ b/docs/development/requirements/02-use_cases.rst @@ -0,0 +1,195 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +Use cases and scenarios +======================= + +Telecom services often have very high requirements on service performance. As a +consequence they often utilize redundancy and high availability (HA) mechanisms +for both the service and the platform. The HA support may be built-in or +provided by the platform. In any case, the HA support typically has a very fast +detection and reaction time to minimize service impact. The main changes +proposed in this document are about making a clear distinction between fault +management and recovery a) within the VIM/NFVI and b) High Availability support +for VNFs on the other, claiming that HA support within a VNF or as a service +from the platform is outside the scope of Doctor and is discussed in the High +Availability for OPNFV project. Doctor should focus on detecting and remediating +faults in the NFVI. This will ensure that applications come back to a fully +redundant configuration faster than before. + +As an example, Telecom services can come with an Active-Standby (ACT-STBY) +configuration which is a (1+1) redundancy scheme. ACT and STBY nodes (aka +Physical Network Function (PNF) in ETSI NFV terminology) are in a hot standby +configuration. If an ACT node is unable to function properly due to fault or any +other reason, the STBY node is instantly made ACT, and affected services can be +provided without any service interruption. + +The ACT-STBY configuration needs to be maintained. This means, when a STBY node +is made ACT, either the previously ACT node, after recovery, shall be made STBY, +or, a new STBY node needs to be configured. The actual operations to +instantiate/configure a new STBY are similar to instantiating a new VNF and +therefore are outside the scope of this project. + +The NFVI fault management and maintenance requirements aim at providing fast +failure detection of physical and virtualized resources and remediation of the +virtualized resources provided to Consumers according to their predefined +request to enable applications to recover to a fully redundant mode of +operation. + +1. Fault management/recovery using ACT-STBY configuration (Triggered by critical + error) +2. Preventive actions based on fault prediction (Preventing service stop by + handling warnings) +3. VM Retirement (Managing service during NFVI maintenance, i.e. H/W, + Hypervisor, Host OS, maintenance) + +Faults +------ + +.. _uc-fault1: + +Fault management using ACT-STBY configuration +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In :numref:`figure1`, a system-wide view of relevant functional blocks is +presented. OpenStack is considered as the VIM implementation (aka Controller) +which has interfaces with the NFVI and the Consumers. The VNF implementation is +represented as different virtual resources marked by different colors. Consumers +(VNFM or NFVO in ETSI NFV terminology) own/manage the respective virtual +resources (VMs in this example) shown with the same colors. + +The first requirement in this use case is that the Controller needs to detect +faults in the NFVI ("1. Fault Notification" in :numref:`figure1`) affecting +the proper functioning of the virtual resources (labelled as VM-x) running on +top of it. It should be possible to configure which relevant fault items should +be detected. The VIM (e.g. OpenStack) itself could be extended to detect such +faults. Alternatively, a third party fault monitoring tool could be used which +then informs the VIM about such faults; this third party fault monitoring +element can be considered as a component of VIM from an architectural point of +view. + +Once such fault is detected, the VIM shall find out which virtual resources are +affected by this fault. In the example in :numref:`figure1`, VM-4 is +affected by a fault in the Hardware Server-3. Such mapping shall be maintained +in the VIM, depicted as the "Server-VM info" table inside the VIM. + +Once the VIM has identified which virtual resources are affected by the fault, +it needs to find out who is the Consumer (i.e. the owner/manager) of the +affected virtual resources (Step 2). In the example shown in :numref:`figure1`, +the VIM knows that for the red VM-4, the manager is the red Consumer +through an Ownership info table. The VIM then notifies (Step 3 "Fault +Notification") the red Consumer about this fault, preferably with sufficient +abstraction rather than detailed physical fault information. + +.. figure:: images/figure1.png + :name: figure1 + :width: 100% + + Fault management/recovery use case + +The Consumer then switches to STBY configuration by switching the STBY node to +ACT state (Step 4). It further initiates a process to instantiate/configure a +new STBY. However, switching to STBY mode and creating a new STBY machine is a +VNFM/NFVO level operation and therefore outside the scope of this project. +Doctor project does not create interfaces for such VNFM level configuration +operations. Yet, since the total failover time of a consumer service depends on +both the delay of such processes as well as the reaction time of Doctor +components, minimizing Doctor's reaction time is a necessary basic ingredient to +fast failover times in general. + +Once the Consumer has switched to STBY configuration, it notifies (Step 5 +"Instruction" in :numref:`figure1`) the VIM. The VIM can then take +necessary (e.g. pre-determined by the involved network operator) actions on how +to clean up the fault affected VMs (Step 6 "Execute Instruction"). + +The key issue in this use case is that a VIM (OpenStack in this context) shall +not take a standalone fault recovery action (e.g. migration of the affected VMs) +before the ACT-STBY switching is complete, as that might violate the ACT-STBY +configuration and render the node out of service. + +As an extension of the 1+1 ACT-STBY resilience pattern, a STBY instance can act as +backup to N ACT nodes (N+1). In this case, the basic information flow remains +the same, i.e., the consumer is informed of a failure in order to activate the +STBY node. However, in this case it might be useful for the failure notification +to cover a number of failed instances due to the same fault (e.g., more than one +instance might be affected by a switch failure). The reaction of the consumer +might depend on whether only one active instance has failed (similar to the +ACT-STBY case), or if more active instances are needed as well. + +Preventive actions based on fault prediction +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The fault management scenario explained in :ref:`uc-fault1` can also be +performed based on fault prediction. In such cases, in VIM, there is an +intelligent fault prediction module which, based on its NFVI monitoring +information, can predict an imminent fault in the elements of NFVI. +A simple example is raising temperature of a Hardware Server which might +trigger a pre-emptive recovery action. The requirements of such fault +prediction in the VIM are investigated in the OPNFV project "Data Collection +for Failure Prediction" [PRED]_. + +This use case is very similar to :ref:`uc-fault1`. Instead of a fault +detection (Step 1 "Fault Notification in" :numref:`figure1`), the trigger +comes from a fault prediction module in the VIM, or from a third party module +which notifies the VIM about an imminent fault. From Step 2~5, the work flow is +the same as in the "Fault management using ACT-STBY configuration" use case, +except in this case, the Consumer of a VM/VNF switches to STBY configuration +based on a predicted fault, rather than an occurred fault. + +NFVI Maintenance +---------------- + +VM Retirement +^^^^^^^^^^^^^ + +All network operators perform maintenance of their network infrastructure, both +regularly and irregularly. Besides the hardware, virtualization is expected to +increase the number of elements subject to such maintenance as NFVI holds new +elements like the hypervisor and host OS. Maintenance of a particular resource +element e.g. hardware, hypervisor etc. may render a particular server hardware +unusable until the maintenance procedure is complete. + +However, the Consumer of VMs needs to know that such resources will be +unavailable because of NFVI maintenance. The following use case is again to +ensure that the ACT-STBY configuration is not violated. A stand-alone action +(e.g. live migration) from VIM/OpenStack to empty a physical machine so that +consequent maintenance procedure could be performed may not only violate the +ACT-STBY configuration, but also have impact on real-time processing scenarios +where dedicated resources to virtual resources (e.g. VMs) are necessary and a +pause in operation (e.g. vCPU) is not allowed. The Consumer is in a position to +safely perform the switch between ACT and STBY nodes, or switch to an +alternative VNF forwarding graph so the hardware servers hosting the ACT nodes +can be emptied for the upcoming maintenance operation. Once the target hardware +servers are emptied (i.e. no virtual resources are running on top), the VIM can +mark them with an appropriate flag (i.e. "maintenance" state) such that these +servers are not considered for hosting of virtual machines until the maintenance +flag is cleared (i.e. nodes are back in "normal" status). + +A high-level view of the maintenance procedure is presented in :numref:`figure2`. +VIM/OpenStack, through its northbound interface, receives a maintenance notification +(Step 1 "Maintenance Request") from the Administrator (e.g. a network operator) +including information about which hardware is subject to maintenance. +Maintenance operations include replacement/upgrade of hardware, +update/upgrade of the hypervisor/host OS, etc. + +The consequent steps to enable the Consumer to perform ACT-STBY switching are +very similar to the fault management scenario. From VIM/OpenStack's internal +database, it finds out which virtual resources (VM-x) are running on those +particular Hardware Servers and who are the managers of those virtual resources +(Step 2). The VIM then informs the respective Consumer (VNFMs or NFVO) in Step 3 +"Maintenance Notification". Based on this, the Consumer takes necessary actions +(Step 4, e.g. switch to STBY configuration or switch VNF forwarding graphs) and +then notifies (Step 5 "Instruction") the VIM. Upon receiving such notification, +the VIM takes necessary actions (Step 6 "Execute Instruction" to empty the +Hardware Servers so that consequent maintenance operations could be performed. +Due to the similarity for Steps 2~6, the maintenance procedure and the fault +management procedure are investigated in the same project. + +.. figure:: images/figure2.png + :name: figure2 + :width: 100% + + Maintenance use case + +.. + vim: set tabstop=4 expandtab textwidth=80: diff --git a/docs/development/requirements/03-architecture.rst b/docs/development/requirements/03-architecture.rst new file mode 100644 index 00000000..b7417691 --- /dev/null +++ b/docs/development/requirements/03-architecture.rst @@ -0,0 +1,340 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +High level architecture and general features +============================================ + +Functional overview +------------------- + +The Doctor project circles around two distinct use cases: 1) management of +failures of virtualized resources and 2) planned maintenance, e.g. migration, of +virtualized resources. Both of them may affect a VNF/application and the network +service it provides, but there is a difference in frequency and how they can be +handled. + +Failures are spontaneous events that may or may not have an impact on the +virtual resources. The Consumer should as soon as possible react to the failure, +e.g., by switching to the STBY node. The Consumer will then instruct the VIM on +how to clean up or repair the lost virtual resources, i.e. restore the VM, VLAN +or virtualized storage. How much the applications are affected varies. +Applications with built-in HA support might experience a short decrease in +retainability (e.g. an ongoing session might be lost) while keeping availability +(establishment or re-establishment of sessions are not affected), whereas the +impact on applications without built-in HA may be more serious. How much the +network service is impacted depends on how the service is implemented. With +sufficient network redundancy the service may be unaffected even when a specific +resource fails. + +On the other hand, planned maintenance impacting virtualized resources are events +that are known in advance. This group includes e.g. migration due to software +upgrades of OS and hypervisor on a compute host. Some of these might have been +requested by the application or its management solution, but there is also a +need for coordination on the actual operations on the virtual resources. There +may be an impact on the applications and the service, but since they are not +spontaneous events there is room for planning and coordination between the +application management organization and the infrastructure management +organization, including performing whatever actions that would be required to +minimize the problems. + +Failure prediction is the process of pro-actively identifying situations that +may lead to a failure in the future unless acted on by means of maintenance +activities. From applications' point of view, failure prediction may impact them +in two ways: either the warning time is so short that the application or its +management solution does not have time to react, in which case it is equal to +the failure scenario, or there is sufficient time to avoid the consequences by +means of maintenance activities, in which case it is similar to planned +maintenance. + +Architecture Overview +--------------------- + +NFV and the Cloud platform provide virtual resources and related control +functionality to users and administrators. :numref:`figure3` shows the high +level architecture of NFV focusing on the NFVI, i.e., the virtualized +infrastructure. The NFVI provides virtual resources, such as virtual machines +(VM) and virtual networks. Those virtual resources are used to run applications, +i.e. VNFs, which could be components of a network service which is managed by +the consumer of the NFVI. The VIM provides functionalities of controlling and +viewing virtual resources on hardware (physical) resources to the consumers, +i.e., users and administrators. OpenStack is a prominent candidate for this VIM. +The administrator may also directly control the NFVI without using the VIM. + +Although OpenStack is the target upstream project where the new functional +elements (Controller, Notifier, Monitor, and Inspector) are expected to be +implemented, a particular implementation method is not assumed. Some of these +elements may sit outside of OpenStack and offer a northbound interface to +OpenStack. + +General Features and Requirements +--------------------------------- + +The following features are required for the VIM to achieve high availability of +applications (e.g., MME, S/P-GW) and the Network Services: + +1. Monitoring: Monitor physical and virtual resources. +2. Detection: Detect unavailability of physical resources. +3. Correlation and Cognition: Correlate faults and identify affected virtual + resources. +4. Notification: Notify unavailable virtual resources to their Consumer(s). +5. Fencing: Shut down or isolate a faulty resource. +6. Recovery action: Execute actions to process fault recovery and maintenance. + +The time interval between the instant that an event is detected by the +monitoring system and the Consumer notification of unavailable resources shall +be < 1 second (e.g., Step 1 to Step 4 in :numref:`figure4`). + +.. figure:: images/figure3.png + :name: figure3 + :width: 100% + + High level architecture + +Monitoring +^^^^^^^^^^ + +The VIM shall monitor physical and virtual resources for unavailability and +suspicious behavior. + +Detection +^^^^^^^^^ + +The VIM shall detect unavailability and failures of physical resources that +might cause errors/faults in virtual resources running on top of them. +Unavailability of physical resource is detected by various monitoring and +managing tools for hardware and software components. This may include also +predicting upcoming faults. Note, fault prediction is out of scope of this +project and is investigated in the OPNFV "Data Collection for Failure +Prediction" project [PRED]_. + +The fault items/events to be detected shall be configurable. + +The configuration shall enable Failure Selection and Aggregation. Failure +aggregation means the VIM determines unavailability of physical resource from +more than two non-critical failures related to the same resource. + +There are two types of unavailability - immediate and future: + +* Immediate unavailability can be detected by setting traps of raw failures on + hardware monitoring tools. +* Future unavailability can be found by receiving maintenance instructions + issued by the administrator of the NFVI or by failure prediction mechanisms. + +Correlation and Cognition +^^^^^^^^^^^^^^^^^^^^^^^^^ + +The VIM shall correlate each fault to the impacted virtual resource, i.e., the +VIM shall identify unavailability of virtualized resources that are or will be +affected by failures on the physical resources under them. Unavailability of a +virtualized resource is determined by referring to the mapping of physical and +virtualized resources. + +VIM shall allow configuration of fault correlation between physical and +virtual resources. VIM shall support correlating faults: + +* between a physical resource and another physical resource +* between a physical resource and a virtual resource +* between a virtual resource and another virtual resource + +Failure aggregation is also required in this feature, e.g., a user may request +to be only notified if failures on more than two standby VMs in an (N+M) +deployment model occurred. + +Notification +^^^^^^^^^^^^ + +The VIM shall notify the alarm, i.e., unavailability of virtual resource(s), to +the Consumer owning it over the northbound interface, such that the Consumers +impacted by the failure can take appropriate actions to recover from the +failure. + +The VIM shall also notify the unavailability of physical resources to its +Administrator. + +All notifications shall be transferred immediately in order to minimize the +stalling time of the network service and to avoid over assignment caused by +delay of capability updates. + +There may be multiple consumers, so the VIM has to find out the owner of a +faulty resource. Moreover, there may be a large number of virtual and physical +resources in a real deployment, so polling the state of all resources to the VIM +would lead to heavy signaling traffic. Thus, a publication/subscription +messaging model is better suited for these notifications, as notifications are +only sent to subscribed consumers. + +Notifications will be send out along with the configuration by the consumer. +The configuration includes endpoint(s) in which the consumers can specify +multiple targets for the notification subscription, so that various and +multiple receiver functions can consume the notification message. +Also, the conditions for notifications shall be configurable, such that +the consumer can set according policies, e.g. whether it wants to receive +fault notifications or not. + +Note: the VIM should only accept notification subscriptions for each resource +by its owner or administrator. +Notifications to the Consumer about the unavailability of virtualized +resources will include a description of the fault, preferably with sufficient +abstraction rather than detailed physical fault information. + +.. _fencing: + +Fencing +^^^^^^^ +Recovery actions, e.g. safe VM evacuation, have to be preceded by fencing the +failed host. Fencing hereby means to isolate or shut down a faulty resource. +Without fencing -- when the perceived disconnection is due to some transient +or partial failure -- the evacuation might lead into two identical instances +running together and having a dangerous conflict. + +There is a cross-project definition in OpenStack of how to implement +fencing, but there has not been any progress. The general description is +available here: +https://wiki.openstack.org/wiki/Fencing_Instances_of_an_Unreachable_Host + +OpenStack provides some mechanisms that allow fencing of faulty resources. Some +are automatically invoked by the platform itself (e.g. Nova disables the +compute service when libvirtd stops running, preventing new VMs to be scheduled +to that node), while other mechanisms are consumer trigger-based actions (e.g. +Neutron port admin-state-up). For other fencing actions not supported by +OpenStack, the Doctor project may suggest ways to address the gap (e.g. through +means of resourcing to external tools and orchestration methods), or +documenting or implementing them upstream. + +The Doctor Inspector component will be responsible of marking resources down in +the OpenStack and back up if necessary. + +Recovery Action +^^^^^^^^^^^^^^^ + +In the basic :ref:`uc-fault1` use case, no automatic actions will be taken by +the VIM, but all recovery actions executed by the VIM and the NFVI will be +instructed and coordinated by the Consumer. + +In a more advanced use case, the VIM may be able to recover the failed virtual +resources according to a pre-defined behavior for that resource. In principle +this means that the owner of the resource (i.e., its consumer or administrator) +can define which recovery actions shall be taken by the VIM. Examples are a +restart of the VM or migration/evacuation of the VM. + + + +High level northbound interface specification +--------------------------------------------- + +Fault Management +^^^^^^^^^^^^^^^^ + +This interface allows the Consumer to subscribe to fault notification from the +VIM. Using a filter, the Consumer can narrow down which faults should be +notified. A fault notification may trigger the Consumer to switch from ACT to +STBY configuration and initiate fault recovery actions. A fault query +request/response message exchange allows the Consumer to find out about active +alarms at the VIM. A filter can be used to narrow down the alarms returned in +the response message. + +.. figure:: images/figure4.png + :name: figure4 + :width: 100% + + High-level message flow for fault management + +The high level message flow for the fault management use case is shown in +:numref:`figure4`. +It consists of the following steps: + +1. The VIM monitors the physical and virtual resources and the fault management + workflow is triggered by a monitored fault event. +2. Event correlation, fault detection and aggregation in VIM. Note: this may + also happen after Step 3. +3. Database lookup to find the virtual resources affected by the detected fault. +4. Fault notification to Consumer. +5. The Consumer switches to standby configuration (STBY). +6. Instructions to VIM requesting certain actions to be performed on the + affected resources, for example migrate/update/terminate specific + resource(s). After reception of such instructions, the VIM is executing the + requested action, e.g., it will migrate or terminate a virtual resource. + +NFVI Maintenance +^^^^^^^^^^^^^^^^ + +The NFVI maintenance interface allows the Administrator to notify the VIM about +a planned maintenance operation on the NFVI. A maintenance operation may for +example be an update of the server firmware or the hypervisor. The +MaintenanceRequest message contains instructions to change the state of the +physical resource from 'enabled' to 'going-to-maintenance' and a timeout [#timeout]_. +After receiving the MaintenanceRequest,the VIM decides on the actions to be taken +based on maintenance policies predefined by the affected Consumer(s). + +.. [#timeout] Timeout is set by the Administrator and corresponds to the maximum time + to empty the physical resources. + +.. figure:: images/figure5a.png + :name: figure5a + :width: 100% + + High-level message flow for maintenance policy enforcement + +The high level message flow for the NFVI maintenance policy enforcement is shown +in :numref:`figure5a`. It consists of the following steps: + +1. Maintenance trigger received from Administrator. +2. VIM switches the affected physical resources to "going-to-maintenance" state e.g. so that no new + VM will be scheduled on the physical servers. +3. Database lookup to find the Consumer(s) and virtual resources affected by the maintenance + operation. +4. Maintenance policies are enforced in the VIM, e.g. affected VM(s) are shut down + on the physical server(s), or affected Consumer(s) are notified about the planned + maintenance operation (steps 4a/4b). + + +Once the affected Consumer(s) have been notified, they take specific actions (e.g. switch to standby +(STBY) configuration, request to terminate the virtual resource(s)) to allow the maintenance +action to be executed. After the physical resources have been emptied, the VIM puts the physical +resources in "in-maintenance" state and sends a MaintenanceResponse back to the Administrator. + +.. figure:: images/figure5b.png + :name: figure5b + :width: 100% + + Successful NFVI maintenance + +The high level message flow for a successful NFVI maintenance is show in :numref:`figure5b`. +It consists of the following steps: + +5. The Consumer C3 switches to standby configuration (STBY). +6. Instructions from Consumers C2/C3 are shared to VIM requesting certain actions to be performed + (steps 6a, 6b). After receiving such instructions, the VIM executes the requested + action in order to empty the physical resources (step 6c) and informs the + Consumer about the result of the actions (steps 6d, 6e). +7. The VIM switches the physical resources to "in-maintenance" state +8. Maintenance response is sent from VIM to inform the Administrator that the physical + servers have been emptied. +9. The Administrator is coordinating and executing the maintenance + operation/work on the NFVI. Note: this step is out of scope of Doctor project. + +The requested actions to empty the physical resources may not be successful (e.g. migration fails +or takes too long) and in such a case, the VIM puts the physical resources back to 'enabled' and +informs the Administrator about the problem. + +.. figure:: images/figure5c.png + :name: figure5c + :width: 100% + + Example of failed NFVI maintenance + +An example of a high level message flow to cover the failed NFVI maintenance case is +shown in :numref:`figure5c`. +It consists of the following steps: + +5. The Consumer C3 switches to standby configuration (STBY). +6. Instructions from Consumers C2/C3 are shared to VIM requesting certain actions to be performed + (steps 6a, 6b). The VIM executes the requested actions and sends back a NACK to consumer C2 + (step 6d) as the migration of the virtual resource(s) is not completed by the given timeout. +7. The VIM switches the physical resources to "enabled" state. +8. MaintenanceNotification is sent from VIM to inform the Administrator that the maintenance action + cannot start. + + +.. + vim: set tabstop=4 expandtab textwidth=80: + diff --git a/docs/development/requirements/04-gaps.rst b/docs/development/requirements/04-gaps.rst new file mode 100644 index 00000000..b8ff7f2e --- /dev/null +++ b/docs/development/requirements/04-gaps.rst @@ -0,0 +1,389 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +Gap analysis in upstream projects +================================= + +This section presents the findings of gaps on existing VIM platforms. The focus +was to identify gaps based on the features and requirements specified in Section +3.3. The analysis work determined gaps that are presented here. + +VIM Northbound Interface +------------------------ + +Immediate Notification +^^^^^^^^^^^^^^^^^^^^^^ + +* Type: 'deficiency in performance' +* Description + + + To-be + + - VIM has to notify unavailability of virtual resource (fault) to VIM user + immediately. + - Notification should be passed in '1 second' after fault detected/notified + by VIM. + - Also, the following conditions/requirement have to be met: + + - Only the owning user can receive notification of fault related to owned + virtual resource(s). + + + As-is + + - OpenStack Metering 'Ceilometer' can notify unavailability of virtual + resource (fault) to the owner of virtual resource based on alarm + configuration by the user. + + - Ceilometer Alarm API: + http://docs.openstack.org/developer/ceilometer/webapi/v2.html#alarms + + - Alarm notifications are triggered by alarm evaluator instead of + notification agents that might receive faults + + - Ceilometer Architecture: + http://docs.openstack.org/developer/ceilometer/architecture.html#id1 + + - Evaluation interval should be equal to or larger than configured pipeline + interval for collection of underlying metrics. + + - https://github.com/openstack/ceilometer/blob/stable/juno/ceilometer/alarm/service.py#L38-42 + + - The interval for collection has to be set large enough which depends on + the size of the deployment and the number of metrics to be collected. + - The interval may not be less than one second in even small deployments. + The default value is 60 seconds. + - Alternative: OpenStack has a message bus to publish system events. + The operator can allow the user to connect this, but there are no + functions to filter out other events that should not be passed to the user + or which were not requested by the user. + + + Gap + + - Fault notifications cannot be received immediately by Ceilometer. + +* Solved by + + + Event Alarm Evaluator: + https://specs.openstack.org/openstack/ceilometer-specs/specs/liberty/event-alarm-evaluator.html + + New OpenStack alarms and notifications project AODH: + http://docs.openstack.org/developer/aodh/ + +Maintenance Notification +^^^^^^^^^^^^^^^^^^^^^^^^ + +* Type: 'missing' +* Description + + + To-be + + - VIM has to notify unavailability of virtual resource triggered by NFVI + maintenance to VIM user. + - Also, the following conditions/requirements have to be met: + + - VIM should accept maintenance message from administrator and mark target + physical resource "in maintenance". + - Only the owner of virtual resource hosted by target physical resource + can receive the notification that can trigger some process for + applications which are running on the virtual resource (e.g. cut off + VM). + + + As-is + + - OpenStack: None + - AWS (just for study) + + - AWS provides API and CLI to view status of resource (VM) and to create + instance status and system status alarms to notify you when an instance + has a failed status check. + http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-instances-status-check_sched.html + - AWS provides API and CLI to view scheduled events, such as a reboot or + retirement, for your instances. Also, those events will be notified + via e-mail. + http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-system-instance-status-check.html + + + Gap + + - VIM user cannot receive maintenance notifications. + +* Solved by + + + https://blueprints.launchpad.net/nova/+spec/service-status-notification + +VIM Southbound interface +------------------------ + +Normalization of data collection models +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +* Type: 'missing' +* Description + + + To-be + + - A normalized data format needs to be created to cope with the many data + models from different monitoring solutions. + + + As-is + + - Data can be collected from many places (e.g. Zabbix, Nagios, Cacti, + Zenoss). Although each solution establishes its own data models, no common + data abstraction models exist in OpenStack. + + + Gap + + - Normalized data format does not exist. + +* Solved by + + + Specification in Section :ref:`southbound`. + +OpenStack +--------- + +Ceilometer +^^^^^^^^^^ + +OpenStack offers a telemetry service, Ceilometer, for collecting measurements of +the utilization of physical and virtual resources [CEIL]_. Ceilometer can +collect a number of metrics across multiple OpenStack components and watch for +variations and trigger alarms based upon the collected data. + +Scalability of fault aggregation +________________________________ + +* Type: 'scalability issue' +* Description + + + To-be + + - Be able to scale to a large deployment, where thousands of monitoring + events per second need to be analyzed. + + + As-is + + - Performance issue when scaling to medium-sized deployments. + + + Gap + + - Ceilometer seems to be unsuitable for monitoring medium and large scale + NFVI deployments. + +* Solved by + + + Usage of Zabbix for fault aggregation [ZABB]_. Zabbix can support a much + higher number of fault events (up to 15 thousand events per second, but + obviously also has some upper bound: + http://blog.zabbix.com/scalable-zabbix-lessons-on-hitting-9400-nvps/2615/ + + + Decentralized/hierarchical deployment with multiple instances, where one + instance is only responsible for a small NFVI. + +Monitoring of hardware and software +___________________________________ + +* Type: 'missing (lack of functionality)' +* Description + + + To-be + + - OpenStack (as VIM) should monitor various hardware and software in NFVI to + handle faults on them by Ceilometer. + - OpenStack may have monitoring functionality in itself and can be + integrated with third party monitoring tools. + - OpenStack need to be able to detect the faults listed in the Annex. + + + As-is + + - For each deployment of OpenStack, an operator has responsibility to + configure monitoring tools with relevant scripts or plugins in order to + monitor hardware and software. + - OpenStack Ceilometer does not monitor hardware and software to capture + faults. + + + Gap + + - Ceilometer is not able to detect and handle all faults listed in the Annex. + +* Solved by + + + Use of dedicated monitoring tools like Zabbix or Monasca. + See :ref:`nfvi_faults`. + +Nova +^^^^ + +OpenStack Nova [NOVA]_ is a mature and widely known and used component in +OpenStack cloud deployments. It is the main part of an +"infrastructure-as-a-service" system providing a cloud computing fabric +controller, supporting a wide diversity of virtualization and container +technologies. + +Nova has proven throughout these past years to be highly available and +fault-tolerant. Featuring its own API, it also provides a compatibility API with +Amazon EC2 APIs. + +Correct states when compute host is down +________________________________________ + +* Type: 'missing (lack of functionality)' +* Description + + + To-be + + - The API shall support to change VM power state in case host has failed. + - The API shall support to change nova-compute state. + - There could be single API to change different VM states for all VMs + belonging to a specific host. + - Support external systems that are monitoring the infrastructure and resources + that are able to call the API fast and reliable. + - Resource states are reliable such that correlation actions can be fast and automated. + - User shall be able to read states from OpenStack and trust they are correct. + + + As-is + + - When a VM goes down due to a host HW, host OS or hypervisor failure, + nothing happens in OpenStack. The VMs of a crashed host/hypervisor are + reported to be live and OK through the OpenStack API. + - nova-compute state might change too slowly or the state is not reliable + if expecting also VMs to be down. This leads to ability to schedule VMs + to a failed host and slowness blocks evacuation. + + + Gap + + - OpenStack does not change its states fast and reliably enough. + - The API does not support to have an external system to change states and to + trust the states are reliable (external system has fenced failed host). + - User cannot read all the states from OpenStack nor trust they are right. + +* Solved by + + + https://blueprints.launchpad.net/nova/+spec/mark-host-down + + https://blueprints.launchpad.net/python-novaclient/+spec/support-force-down-service + +Evacuate VMs in Maintenance mode +________________________________ + +* Type: 'missing' +* Description + + + To-be + + - When maintenance mode for a compute host is set, trigger VM evacuation to + available compute nodes before bringing the host down for maintenance. + + + As-is + + - If setting a compute node to a maintenance mode, OpenStack only schedules + evacuation of all VMs to available compute nodes if in-maintenance compute + node runs the XenAPI and VMware ESX hypervisors. Other hypervisors (e.g. + KVM) are not supported and, hence, guest VMs will likely stop running due + to maintenance actions administrator may perform (e.g. hardware upgrades, + OS updates). + + + Gap + + - Nova libvirt hypervisor driver does not implement automatic guest VMs + evacuation when compute nodes are set to maintenance mode (``$ nova + host-update --maintenance enable ``). + +Monasca +^^^^^^^ + +Monasca is an open-source monitoring-as-a-service (MONaaS) solution that +integrates with OpenStack. Even though it is still in its early days, it is the +interest of the community that the platform be multi-tenant, highly scalable, +performant and fault-tolerant. It provides a streaming alarm engine, a +notification engine, and a northbound REST API users can use to interact with +Monasca. Hundreds of thousands of metrics per second can be processed +[MONA]_. + +Anomaly detection +_________________ + + +* Type: 'missing (lack of functionality)' +* Description + + + To-be + + - Detect the failure and perform a root cause analysis to filter out other + alarms that may be triggered due to their cascading relation. + + + As-is + + - A mechanism to detect root causes of failures is not available. + + + Gap + + - Certain failures can trigger many alarms due to their dependency on the + underlying root cause of failure. Knowing the root cause can help filter + out unnecessary and overwhelming alarms. + +* Status + + + Monasca as of now lacks this feature, although the community is aware and + working toward supporting it. + +Sensor monitoring +_________________ + +* Type: 'missing (lack of functionality)' +* Description + + + To-be + + - It should support monitoring sensor data retrieval, for instance, from + IPMI. + + + As-is + + - Monasca does not monitor sensor data + + + Gap + + - Sensor monitoring is very important. It provides operators status + on the state of the physical infrastructure (e.g. temperature, fans). + +* Addressed by + + + Monasca can be configured to use third-party monitoring solutions (e.g. + Nagios, Cacti) for retrieving additional data. + +Hardware monitoring tools +------------------------- + +Zabbix +^^^^^^ + +Zabbix is an open-source solution for monitoring availability and performance of +infrastructure components (i.e. servers and network devices), as well as +applications [ZABB]_. It can be customized for use with OpenStack. It is a +mature tool and has been proven to be able to scale to large systems with +100,000s of devices. + +Delay in execution of actions +_____________________________ + + +* Type: 'deficiency in performance' +* Description + + + To-be + + - After detecting a fault, the monitoring tool should immediately execute + the appropriate action, e.g. inform the manager through the NB I/F + + + As-is + + - A delay of around 10 seconds was measured in two independent testbed + deployments + + + Gap + + - Cause of the delay is a periodic evaluation and notification. Periodicity is configured + as 30s default value and can be reduced to 5s but not below. + https://github.com/zabbix/zabbix/blob/trunk/conf/zabbix_server.conf#L329 + + +.. + vim: set tabstop=4 expandtab textwidth=80: diff --git a/docs/development/requirements/05-implementation.rst b/docs/development/requirements/05-implementation.rst new file mode 100644 index 00000000..84979772 --- /dev/null +++ b/docs/development/requirements/05-implementation.rst @@ -0,0 +1,1050 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +Detailed architecture and interface specification +================================================= + +This section describes a detailed implementation plan, which is based on the +high level architecture introduced in Section 3. Section 5.1 describes the +functional blocks of the Doctor architecture, which is followed by a high level +message flow in Section 5.2. Section 5.3 provides a mapping of selected existing +open source components to the building blocks of the Doctor architecture. +Thereby, the selection of components is based on their maturity and the gap +analysis executed in Section 4. Sections 5.4 and 5.5 detail the specification of +the related northbound interface and the related information elements. Finally, +Section 5.6 provides a first set of blueprints to address selected gaps required +for the realization functionalities of the Doctor project. + +.. _impl_fb: + +Functional Blocks +----------------- + +This section introduces the functional blocks to form the VIM. OpenStack was +selected as the candidate for implementation. Inside the VIM, 4 different +building blocks are defined (see :numref:`figure6`). + +.. figure:: images/figure6.png + :name: figure6 + :width: 100% + + Functional blocks + +Monitor +^^^^^^^ + +The Monitor module has the responsibility for monitoring the virtualized +infrastructure. There are already many existing tools and services (e.g. Zabbix) +to monitor different aspects of hardware and software resources which can be +used for this purpose. + +Inspector +^^^^^^^^^ + +The Inspector module has the ability a) to receive various failure notifications +regarding physical resource(s) from Monitor module(s), b) to find the affected +virtual resource(s) by querying the resource map in the Controller, and c) to +update the state of the virtual resource (and physical resource). + +The Inspector has drivers for different types of events and resources to +integrate any type of Monitor and Controller modules. It also uses a failure +policy database to decide on the failure selection and aggregation from raw +events. This failure policy database is configured by the Administrator. + +The reason for separation of the Inspector and Controller modules is to make the +Controller focus on simple operations by avoiding a tight integration of various +health check mechanisms into the Controller. + +Controller +^^^^^^^^^^ + +The Controller is responsible for maintaining the resource map (i.e. the mapping +from physical resources to virtual resources), accepting update requests for the +resource state(s) (exposing as provider API), and sending all failure events +regarding virtual resources to the Notifier. Optionally, the Controller has the +ability to force the state of a given physical resource to down in the resource +mapping when it receives failure notifications from the Inspector for that +given physical resource. +The Controller also re-calculates the capacity of the NVFI when receiving a +failure notification for a physical resource. + +In a real-world deployment, the VIM may have several controllers, one for each +resource type, such as Nova, Neutron and Cinder in OpenStack. Each controller +maintains a database of virtual and physical resources which shall be the master +source for resource information inside the VIM. + +Notifier +^^^^^^^^ + +The focus of the Notifier is on selecting and aggregating failure events +received from the controller based on policies mandated by the Consumer. +Therefore, it allows the Consumer to subscribe for alarms regarding virtual +resources using a method such as API endpoint. After receiving a fault +event from a Controller, it will notify the fault to the Consumer by referring +to the alarm configuration which was defined by the Consumer earlier on. + +To reduce complexity of the Controller, it is a good approach for the +Controllers to emit all notifications without any filtering mechanism and have +another service (i.e. Notifier) handle those notifications properly. This is the +general philosophy of notifications in OpenStack. Note that a fault message +consumed by the Notifier is different from the fault message received by the +Inspector; the former message is related to virtual resources which are visible +to users with relevant ownership, whereas the latter is related to raw devices +or small entities which should be handled with an administrator privilege. + +The northbound interface between the Notifier and the Consumer/Administrator is +specified in :ref:`impl_nbi`. + +Sequence +-------- + +Fault Management +^^^^^^^^^^^^^^^^ + +The detailed work flow for fault management is as follows (see also :numref:`figure7`): + +1. Request to subscribe to monitor specific virtual resources. A query filter + can be used to narrow down the alarms the Consumer wants to be informed + about. +2. Each subscription request is acknowledged with a subscribe response message. + The response message contains information about the subscribed virtual + resources, in particular if a subscribed virtual resource is in "alarm" + state. +3. The NFVI sends monitoring events for resources the VIM has been subscribed + to. Note: this subscription message exchange between the VIM and NFVI is not + shown in this message flow. +4. Event correlation, fault detection and aggregation in VIM. +5. Database lookup to find the virtual resources affected by the detected fault. +6. Fault notification to Consumer. +7. The Consumer switches to standby configuration (STBY) +8. Instructions to VIM requesting certain actions to be performed on the + affected resources, for example migrate/update/terminate specific + resource(s). After reception of such instructions, the VIM is executing the + requested action, e.g. it will migrate or terminate a virtual resource. +a. Query request from Consumer to VIM to get information about the current + status of a resource. +b. Response to the query request with information about the current status of + the queried resource. In case the resource is in "fault" state, information + about the related fault(s) is returned. + +In order to allow for quick reaction to failures, the time interval between +fault detection in step 3 and the corresponding recovery actions in step 7 and 8 +shall be less than 1 second. + +.. figure:: images/figure7.png + :name: figure7 + :width: 100% + + Fault management work flow + +.. figure:: images/figure8.png + :name: figure8 + :width: 100% + + Fault management scenario + +:numref:`figure8` shows a more detailed message flow (Steps 4 to 6) between +the 4 building blocks introduced in :ref:`impl_fb`. + +4. The Monitor observed a fault in the NFVI and reports the raw fault to the + Inspector. + The Inspector filters and aggregates the faults using pre-configured + failure policies. + +5. + a) The Inspector queries the Resource Map to find the virtual resources + affected by the raw fault in the NFVI. + b) The Inspector updates the state of the affected virtual resources in the + Resource Map. + c) The Controller observes a change of the virtual resource state and informs + the Notifier about the state change and the related alarm(s). + Alternatively, the Inspector may directly inform the Notifier about it. + +6. The Notifier is performing another filtering and aggregation of the changes + and alarms based on the pre-configured alarm configuration. Finally, a fault + notification is sent to northbound to the Consumer. + +NFVI Maintenance +^^^^^^^^^^^^^^^^ +.. figure:: images/figure9.png + :name: figure9 + :width: 100% + + NFVI maintenance work flow + +The detailed work flow for NFVI maintenance is shown in :numref:`figure9` +and has the following steps. Note that steps 1, 2, and 5 to 8a in the NFVI +maintenance work flow are very similar to the steps in the fault management work +flow and share a similar implementation plan in Release 1. + +1. Subscribe to fault/maintenance notifications. +2. Response to subscribe request. +3. Maintenance trigger received from administrator. +4. VIM switches NFVI resources to "maintenance" state. This, e.g., means they + should not be used for further allocation/migration requests +5. Database lookup to find the virtual resources affected by the detected + maintenance operation. +6. Maintenance notification to Consumer. +7. The Consumer switches to standby configuration (STBY) +8. Instructions from Consumer to VIM requesting certain recovery actions to be + performed (step 8a). After reception of such instructions, the VIM is + executing the requested action in order to empty the physical resources (step + 8b). +9. Maintenance response from VIM to inform the Administrator that the physical + machines have been emptied (or the operation resulted in an error state). +10. Administrator is coordinating and executing the maintenance operation/work + on the NFVI. +a) Query request from Administrator to VIM to get information about the + current state of a resource. +b) Response to the query request with information about the current state of + the queried resource(s). In case the resource is in "maintenance" state, + information about the related maintenance operation is returned. + +.. figure:: images/figure10.png + :name: figure10 + :width: 100% + + NFVI Maintenance implementation plan + +:numref:`figure10` shows a more detailed message flow (Steps 3 to 6 and 9) +between the 4 building blocks introduced in Section 5.1.. + +3. The Administrator is sending a StateChange request to the Controller residing + in the VIM. +4. The Controller queries the Resource Map to find the virtual resources + affected by the planned maintenance operation. +5. + + a) The Controller updates the state of the affected virtual resources in the + Resource Map database. + + b) The Controller informs the Notifier about the virtual resources that will + be affected by the maintenance operation. + +6. A maintenance notification is sent to northbound to the Consumer. + +... + +9. The Controller informs the Administrator after the physical resources have + been freed. + + + +Implementation plan for OPNFV Release 1 +--------------------------------------- + +Fault management +^^^^^^^^^^^^^^^^ + +:numref:`figure11` shows the implementation plan based on OpenStack and +related components as planned for Release 1. Hereby, the Monitor can be realized +by Zabbix. The Controller is realized by OpenStack Nova [NOVA]_, Neutron +[NEUT]_, and Cinder [CIND]_ for compute, network, and storage, +respectively. The Inspector can be realized by Monasca [MONA]_ or a simple +script querying Nova in order to map between physical and virtual resources. The +Notifier will be realized by Ceilometer [CEIL]_ receiving failure events +on its notification bus. + +:numref:`figure12` shows the inner-workings of Ceilometer. After receiving +an "event" on its notification bus, first a notification agent will grab the +event and send a "notification" to the Collector. The collector writes the +notifications received to the Ceilometer databases. + +In the existing Ceilometer implementation, an alarm evaluator is periodically +polling those databases through the APIs provided. If it finds new alarms, it +will evaluate them based on the pre-defined alarm configuration, and depending +on the configuration, it will hand a message to the Alarm Notifier, which in +turn will send the alarm message northbound to the Consumer. :numref:`figure12` +also shows an optimized work flow for Ceilometer with the goal to +reduce the delay for fault notifications to the Consumer. The approach is to +implement a new notification agent (called "publisher" in Ceilometer +terminology) which is directly sending the alarm through the "Notification Bus" +to a new "Notification-driven Alarm Evaluator (NAE)" (see Sections 5.6.2 and +5.6.3), thereby bypassing the Collector and avoiding the additional delay of the +existing polling-based alarm evaluator. The NAE is similar to the OpenStack +"Alarm Evaluator", but is triggered by incoming notifications instead of +periodically polling the OpenStack "Alarms" database for new alarms. The +Ceilometer "Alarms" database can hold three states: "normal", "insufficient +data", and "fired". It is representing a persistent alarm database. In order to +realize the Doctor requirements, we need to define new "meters" in the database +(see Section 5.6.1). + +.. figure:: images/figure11.png + :name: figure11 + :width: 100% + + Implementation plan in OpenStack (OPNFV Release 1 ”Arno”) + + +.. figure:: images/figure12.png + :name: figure12 + :width: 100% + + Implementation plan in Ceilometer architecture + + +NFVI Maintenance +^^^^^^^^^^^^^^^^ + +For NFVI Maintenance, a quite similar implementation plan exists. Instead of a +raw fault being observed by the Monitor, the Administrator is sending a +Maintenance Request through the northbound interface towards the Controller +residing in the VIM. Similar to the Fault Management use case, the Controller +(in our case OpenStack Nova) will send a maintenance event to the Notifier (i.e. +Ceilometer in our implementation). Within Ceilometer, the same workflow as +described in the previous section applies. In addition, the Controller(s) will +take appropriate actions to evacuate the physical machines in order to prepare +them for the planned maintenance operation. After the physical machines are +emptied, the Controller will inform the Administrator that it can initiate the +maintenance. Alternatively the VMs can just be shut down and boot up on the +same host after maintenance is over. There needs to be policy for administrator +to know the plan for VMs in maintenance. + +Information elements +-------------------- + +This section introduces all attributes and information elements used in the +messages exchange on the northbound interfaces between the VIM and the VNFO and +VNFM. + +Note: The information elements will be aligned with current work in ETSI NFV IFA +working group. + + +Simple information elements: + +* SubscriptionID (Identifier): identifies a subscription to receive fault or maintenance + notifications. +* NotificationID (Identifier): identifies a fault or maintenance notification. +* VirtualResourceID (Identifier): identifies a virtual resource affected by a + fault or a maintenance action of the underlying physical resource. +* PhysicalResourceID (Identifier): identifies a physical resource affected by a + fault or maintenance action. +* VirtualResourceState (String): state of a virtual resource, e.g. "normal", + "maintenance", "down", "error". +* PhysicalResourceState (String): state of a physical resource, e.g. "normal", + "maintenance", "down", "error". +* VirtualResourceType (String): type of the virtual resource, e.g. "virtual + machine", "virtual memory", "virtual storage", "virtual CPU", or "virtual + NIC". +* FaultID (Identifier): identifies the related fault in the underlying physical + resource. This can be used to correlate different fault notifications caused + by the same fault in the physical resource. +* FaultType (String): Type of the fault. The allowed values for this parameter + depend on the type of the related physical resource. For example, a resource + of type "compute hardware" may have faults of type "CPU failure", "memory + failure", "network card failure", etc. +* Severity (Integer): value expressing the severity of the fault. The higher the + value, the more severe the fault. +* MinSeverity (Integer): value used in filter information elements. Only faults + with a severity higher than the MinSeverity value will be notified to the + Consumer. +* EventTime (Datetime): Time when the fault was observed. +* EventStartTime and EventEndTime (Datetime): Datetime range that can be used in + a FaultQueryFilter to narrow down the faults to be queried. +* ProbableCause (String): information about the probable cause of the fault. +* CorrelatedFaultID (Integer): list of other faults correlated to this fault. +* isRootCause (Boolean): Parameter indicating if this fault is the root for + other correlated faults. If TRUE, then the faults listed in the parameter + CorrelatedFaultID are caused by this fault. +* FaultDetails (Key-value pair): provides additional information about the + fault, e.g. information about the threshold, monitored attributes, indication + of the trend of the monitored parameter. +* FirmwareVersion (String): current version of the firmware of a physical + resource. +* HypervisorVersion (String): current version of a hypervisor. +* ZoneID (Identifier): Identifier of the resource zone. A resource zone is the + logical separation of physical and software resources in an NFVI deployment + for physical isolation, redundancy, or administrative designation. +* Metadata (Key-value pair): provides additional information of a physical + resource in maintenance/error state. + +Complex information elements (see also UML diagrams in :numref:`figure13` +and :numref:`figure14`): + +* VirtualResourceInfoClass: + + + VirtualResourceID [1] (Identifier) + + VirtualResourceState [1] (String) + + Faults [0..*] (FaultClass): For each resource, all faults + including detailed information about the faults are provided. + +* FaultClass: The parameters of the FaultClass are partially based on ETSI TS + 132 111-2 (V12.1.0) [*]_, which is specifying fault management in 3GPP, in + particular describing the information elements used for alarm notifications. + + - FaultID [1] (Identifier) + - FaultType [1] (String) + - Severity [1] (Integer) + - EventTime [1] (Datetime) + - ProbableCause [1] (String) + - CorrelatedFaultID [0..*] (Identifier) + - FaultDetails [0..*] (Key-value pair) + +.. [*] http://www.etsi.org/deliver/etsi_ts/132100_132199/13211102/12.01.00_60/ts_13211102v120100p.pdf + +* SubscribeFilterClass + + - VirtualResourceType [0..*] (String) + - VirtualResourceID [0..*] (Identifier) + - FaultType [0..*] (String) + - MinSeverity [0..1] (Integer) + +* FaultQueryFilterClass: narrows down the FaultQueryRequest, for example it + limits the query to certain physical resources, a certain zone, a given fault + type/severity/cause, or a specific FaultID. + + - VirtualResourceType [0..*] (String) + - VirtualResourceID [0..*] (Identifier) + - FaultType [0..*] (String) + - MinSeverity [0..1] (Integer) + - EventStartTime [0..1] (Datetime) + - EventEndTime [0..1] (Datetime) + +* PhysicalResourceStateClass: + + - PhysicalResourceID [1] (Identifier) + - PhysicalResourceState [1] (String): mandates the new state of the physical + resource. + - Metadata [0..*] (Key-value pair) + +* PhysicalResourceInfoClass: + + - PhysicalResourceID [1] (Identifier) + - PhysicalResourceState [1] (String) + - FirmwareVersion [0..1] (String) + - HypervisorVersion [0..1] (String) + - ZoneID [0..1] (Identifier) + - Metadata [0..*] (Key-value pair) + +* StateQueryFilterClass: narrows down a StateQueryRequest, for example it limits + the query to certain physical resources, a certain zone, or a given resource + state (e.g., only resources in "maintenance" state). + + - PhysicalResourceID [1] (Identifier) + - PhysicalResourceState [1] (String) + - ZoneID [0..1] (Identifier) + +.. _impl_nbi: + +Detailed northbound interface specification +------------------------------------------- + +This section is specifying the northbound interfaces for fault management and +NFVI maintenance between the VIM on the one end and the Consumer and the +Administrator on the other ends. For each interface all messages and related +information elements are provided. + +Note: The interface definition will be aligned with current work in ETSI NFV IFA +working group . + +All of the interfaces described below are produced by the VIM and consumed by +the Consumer or Administrator. + +Fault management interface +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +This interface allows the VIM to notify the Consumer about a virtual resource +that is affected by a fault, either within the virtual resource itself or by the +underlying virtualization infrastructure. The messages on this interface are +shown in :numref:`figure13` and explained in detail in the following +subsections. + +Note: The information elements used in this section are described in detail in +Section 5.4. + +.. figure:: images/figure13.png + :name: figure13 + :width: 100% + + Fault management NB I/F messages + + +SubscribeRequest (Consumer -> VIM) +__________________________________ + +Subscription from Consumer to VIM to be notified about faults of specific +resources. The faults to be notified about can be narrowed down using a +subscribe filter. + +Parameters: + +- SubscribeFilter [1] (SubscribeFilterClass): Optional information to narrow + down the faults that shall be notified to the Consumer, for example limit to + specific VirtualResourceID(s), severity, or cause of the alarm. + +SubscribeResponse (VIM -> Consumer) +___________________________________ + +Response to a subscribe request message including information about the +subscribed resources, in particular if they are in "fault/error" state. + +Parameters: + +* SubscriptionID [1] (Identifier): Unique identifier for the subscription. It + can be used to delete or update the subscription. +* VirtualResourceInfo [0..*] (VirtualResourceInfoClass): Provides additional + information about the subscribed resources, i.e., a list of the related + resources, the current state of the resources, etc. + +FaultNotification (VIM -> Consumer) +___________________________________ + +Notification about a virtual resource that is affected by a fault, either within +the virtual resource itself or by the underlying virtualization infrastructure. +After reception of this request, the Consumer will decide on the optimal +action to resolve the fault. This includes actions like switching to a hot +standby virtual resource, migration of the fault virtual resource to another +physical machine, termination of the faulty virtual resource and instantiation +of a new virtual resource in order to provide a new hot standby resource. In +some use cases the Consumer can leave virtual resources on failed host to be +booted up again after fault is recovered. Existing resource management +interfaces and messages between the Consumer and the VIM can be used for those +actions, and there is no need to define additional actions on the Fault +Management Interface. + +Parameters: + +* NotificationID [1] (Identifier): Unique identifier for the notification. +* VirtualResourceInfo [1..*] (VirtualResourceInfoClass): List of faulty + resources with detailed information about the faults. + +FaultQueryRequest (Consumer -> VIM) +___________________________________ + +Request to find out about active alarms at the VIM. A FaultQueryFilter can be +used to narrow down the alarms returned in the response message. + +Parameters: + +* FaultQueryFilter [1] (FaultQueryFilterClass): narrows down the + FaultQueryRequest, for example it limits the query to certain physical + resources, a certain zone, a given fault type/severity/cause, or a specific + FaultID. + +FaultQueryResponse (VIM -> Consumer) +____________________________________ + +List of active alarms at the VIM matching the FaultQueryFilter specified in the +FaultQueryRequest. + +Parameters: + +* VirtualResourceInfo [0..*] (VirtualResourceInfoClass): List of faulty + resources. For each resource all faults including detailed information about + the faults are provided. + +NFVI maintenance +^^^^^^^^^^^^^^^^ + +The NFVI maintenance interfaces Consumer-VIM allows the Consumer to subscribe to +maintenance notifications provided by the VIM. The related maintenance interface +Administrator-VIM allows the Administrator to issue maintenance requests to the +VIM, i.e. requesting the VIM to take appropriate actions to empty physical +machine(s) in order to execute maintenance operations on them. The interface +also allows the Administrator to query the state of physical machines, e.g., in +order to get details in the current status of the maintenance operation like a +firmware update. + +The messages defined in these northbound interfaces are shown in :numref:`figure14` +and described in detail in the following subsections. + +.. figure:: images/figure14.png + :name: figure14 + :width: 100% + + NFVI maintenance NB I/F messages + +SubscribeRequest (Consumer -> VIM) +__________________________________ + +Subscription from Consumer to VIM to be notified about maintenance operations +for specific virtual resources. The resources to be informed about can be +narrowed down using a subscribe filter. + +Parameters: + +* SubscribeFilter [1] (SubscribeFilterClass): Information to narrow down the + faults that shall be notified to the Consumer, for example limit to specific + virtual resource type(s). + +SubscribeResponse (VIM -> Consumer) +___________________________________ + +Response to a subscribe request message, including information about the +subscribed virtual resources, in particular if they are in "maintenance" state. + +Parameters: + +* SubscriptionID [1] (Identifier): Unique identifier for the subscription. It + can be used to delete or update the subscription. +* VirtualResourceInfo [0..*] (VirtalResourceInfoClass): Provides additional + information about the subscribed virtual resource(s), e.g., the ID, type and + current state of the resource(s). + +MaintenanceNotification (VIM -> Consumer) +_________________________________________ + +Notification about a physical resource switched to "maintenance" state. After +reception of this request, the Consumer will decide on the optimal action to +address this request, e.g., to switch to the standby (STBY) configuration. + +Parameters: + +* VirtualResourceInfo [1..*] (VirtualResourceInfoClass): List of virtual + resources where the state has been changed to maintenance. + +StateChangeRequest (Administrator -> VIM) +_________________________________________ + +Request to change the state of a list of physical resources, e.g. to +"maintenance" state, in order to prepare them for a planned maintenance +operation. + +Parameters: + +* PhysicalResourceState [1..*] (PhysicalResourceStateClass) + +StateChangeResponse (VIM -> Administrator) +__________________________________________ + +Response message to inform the Administrator that the requested resources are +now in maintenance state (or the operation resulted in an error) and the +maintenance operation(s) can be executed. + +Parameters: + +* PhysicalResourceInfo [1..*] (PhysicalResourceInfoClass) + +StateQueryRequest (Administrator -> VIM) +________________________________________ + +In this procedure, the Administrator would like to get the information about +physical machine(s), e.g. their state ("normal", "maintenance"), firmware +version, hypervisor version, update status of firmware and hypervisor, etc. It +can be used to check the progress during firmware update and the confirmation +after update. A filter can be used to narrow down the resources returned in the +response message. + +Parameters: + +* StateQueryFilter [1] (StateQueryFilterClass): narrows down the + StateQueryRequest, for example it limits the query to certain physical + resources, a certain zone, or a given resource state. + +StateQueryResponse (VIM -> Administrator) +_________________________________________ + +List of physical resources matching the filter specified in the +StateQueryRequest. + +Parameters: + +* PhysicalResourceInfo [0..*] (PhysicalResourceInfoClass): List of physical + resources. For each resource, information about the current state, the + firmware version, etc. is provided. + +NFV IFA, OPNFV Doctor and AODH alarms +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +This section compares the alarm interfaces of ETSI NFV IFA with the specifications +of this document and the alarm class of AODH. + +ETSI NFV specifies an interface for alarms from virtualised resources in ETSI GS +NFV-IFA 005 [ENFV]_. The interface specifies an Alarm class and two notifications plus +operations to query alarm instances and to subscribe to the alarm notifications. + +The specification in this document has a structure that is very similar to the +ETSI NFV specifications. The notifications differ in that an alarm notification +in the NFV interface defines a single fault for a single resource while the +notification specified in this document can contain multiple faults for +multiple resources. The Doctor specification is lacking the detailed time stamps +of the NFV specification essential for synchronizaion of the alarm list +using the query operation. The detailed time stamps are also of value in the event +and alarm history DBs. + +AODH defines a base class for alarms, not the notifications. This means that +some of the dynamic attributes of the ETSI NFV alarm type, like alarmRaisedTime, +are not applicable to the AODH alarm class but are attributes of in the actual +notifications. (Description of these attributes will be added later.) The AODH alarm +class is lacking some attributes present in the NFV specification, fault details +and correlated alarms. Instead the AODH alarm class has attributes for actions, +rules and user and project id. + + ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| ETSI NFV Alarm Type | OPNFV Doctor | AODH Event Alarm | Description / Comment | Recommendations | +| | Requirement Specs | Notification | | | ++========================+========================+=====================+=============================================+=======================================+ +| alarmId | FaultId | alarm_id | Identifier of an alarm. | \- | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| \- | \- | alarm_name | Human readable alarm name. | May be added in ETSI NFV Stage 3. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| managedObjectId | VirtualResourceId | (reason) | Identifier of the affected virtual resource | \- | +| | | | is part of the AODH reason parameter. | | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| \- | \- | user_id, project_id | User and project identifiers. | May be added in ETSI NFV Stage 3. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| alarmRaisedTime | \- | \- | Timestamp when alarm was raised. | To be added to Doctor and AODH. May | +| | | | | be derived (e.g. in a shimlayer) from | +| | | | | the AODH alarm history. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| alarmChangedTime | \- | \- | Timestamp when alarm was changed/updated. | see above | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| alarmClearedTime | \- | \- | Timestamp when alarm was cleared. | see above | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| eventTime | \- | \- | Timestamp when alarm was first observed by | see above | +| | | | the Monitor. | | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| \- | EventTime | generated | Timestamp of the Notification. | Update parameter name in Doctor spec. | +| | | | | May be added in ETSI NFV Stage 3. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| state: | VirtualResourceState: | current: ok, alarm, | ETSI NFV IFA 005/006 lists example alarm | Maintenance state is missing in AODH. | +| E.g. Fired, Updated | E.g. normal, down | insufficient_data | states. | List of alarm states will be | +| Cleared | maintenance, error | | | specified in ETSI NFV Stage 3. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| perceivedSeverity: | Severity (Integer) | Severity: | ETSI NFV IFA 005/006 lists example | List of alarm states will be | +| E.g. Critical, Major, | | low (default), | perceived severity values. | specified in ETSI NFV Stage 3. | +| Minor, Warning, | | moderate, critical | | | +| Indeterminate, Cleared | | | | **OPNFV: Severity (Integer)**: | +| | | | | * update OPNFV Doctor specification | +| | | | | to *Enum* | +| | | | | | +| | | | | **perceivedSeverity=Indetermined**: | +| | | | | * remove value *Indetermined* in | +| | | | | IFA and map undefined values to | +| | | | | “minor” severity, or | +| | | | | * add value *indetermined* in AODH | +| | | | | and make it the default value. | +| | | | | | +| | | | | **perceivedSeverity=Cleared**: | +| | | | | * remove value *Cleared* in IFA as | +| | | | | the information about a cleared | +| | | | | alarm alarm can be derived from | +| | | | | the alarm state parameter, or | +| | | | | * add value *cleared* in AODH and | +| | | | | set a rule that the severity is | +| | | | | “cleared” when the state is *ok*. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| faultType | FaultType | event_type in | Type of the fault, e.g. “CPU failure” of a | OpenStack Alarming (Aodh) can use a | +| | | reason_data | compute resource, in machine interpretable | fuzzy matching with wildcard string, | +| | | | format. | "compute.cpu.failure". | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| N/A | N/A | type = "event" | Type of the notification. For fault | \- | +| | | | notifications the type in AODH is “event”. | | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| probableCause | ProbableCause | \- | Probable cause of the alarm. | May be provided (e.g. in a shimlayer) | +| | | | | based on Vitrage topology awareness / | +| | | | | root-cause-analysis. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| isRootCause | IsRootCause | \- | Boolean indicating whether the fault is the | see above | +| | | | root cause of other faults. | | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| correlatedAlarmId | CorrelatedFaultId | \- | List of IDs of correlated faults. | see above | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| faultDetails | FaultDetails | \- | Additional details about the fault/alarm. | FaultDetails information element will | +| | | | | be specified in ETSI NFV Stage 3. | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ +| \- | \- | action, previous | Additional AODH alarm related parameters. | \- | ++------------------------+------------------------+---------------------+---------------------------------------------+---------------------------------------+ + +Table: Comparison of alarm attributes + +The primary area of improvement should be alignment of the perceived severity. This +is important for a quick and accurate evaluation of the alarm. AODH thus should +support also the X.733 values Critical, Major, Minor, Warning and Indeterminate. + +The detailed time stamps (raised, changed, cleared) which are essential for +synchronizing the alarm list using a query operation should be added to the +Doctor specification. + +Other areas that need alignment is the so called alarm state in NFV. Here we must +however consider what can be attributes of the notification vs. what should be a +property of the alarm instance. This will be analyzed later. + +.. _southbound: + +Detailed southbound interface specification +------------------------------------------- + +This section is specifying the southbound interfaces for fault management +between the Monitors and the Inspector. +Although southbound interfaces should be flexible to handle various events from +different types of Monitors, we define unified event API in order to improve +interoperability between the Monitors and the Inspector. +This is not limiting implementation of Monitor and Inspector as these could be +extended in order to support failures from intelligent inspection like prediction. + +Note: The interface definition will be aligned with current work in ETSI NFV IFA +working group. + +Fault event interface +^^^^^^^^^^^^^^^^^^^^^ + +This interface allows the Monitors to notify the Inspector about an event which +was captured by the Monitor and may effect resources managed in the VIM. + +EventNotification +_________________ + + +Event notification including fault description. +The entity of this notification is event, and not fault or error specifically. +This allows us to use generic event format or framework build out of Doctor project. +The parameters below shall be mandatory, but keys in 'Details' can be optional. + +Parameters: + +* Time [1]: Datetime when the fault was observed in the Monitor. +* Type [1]: Type of event that will be used to process correlation in Inspector. +* Details [0..1]: Details containing additional information with Key-value pair style. + Keys shall be defined depending on the Type of the event. + +E.g.: + +.. code-block:: bash + + { + 'event': { + 'time': '2016-04-12T08:00:00', + 'type': 'compute.host.down', + 'details': { + 'hostname': 'compute-1', + 'source': 'sample_monitor', + 'cause': 'link-down', + 'severity': 'critical', + 'status': 'down', + 'monitor_id': 'monitor-1', + 'monitor_event_id': '123', + } + } + } + +Optional parameters in 'Details': + +* Hostname: the hostname on which the event occurred. +* Source: the display name of reporter of this event. This is not limited to monitor, other entity can be specified such as 'KVM'. +* Cause: description of the cause of this event which could be different from the type of this event. +* Severity: the severity of this event set by the monitor. +* Status: the status of target object in which error occurred. +* MonitorID: the ID of the monitor sending this event. +* MonitorEventID: the ID of the event in the monitor. This can be used by operator while tracking the monitor log. +* RelatedTo: the array of IDs which related to this event. + +Also, we can have bulk API to receive multiple events in a single HTTP POST +message by using the 'events' wrapper as follows: + +.. code-block:: bash + + { + 'events': [ + 'event': { + 'time': '2016-04-12T08:00:00', + 'type': 'compute.host.down', + 'details': {}, + }, + 'event': { + 'time': '2016-04-12T08:00:00', + 'type': 'compute.host.nic.error', + 'details': {}, + } + ] + } + + + + +Blueprints +---------- + +This section is listing a first set of blueprints that have been proposed by the +Doctor project to the open source community. Further blueprints addressing other +gaps identified in Section 4 will be submitted at a later stage of the OPNFV. In +this section the following definitions are used: + +* "Event" is a message emitted by other OpenStack services such as Nova and + Neutron and is consumed by the "Notification Agents" in Ceilometer. +* "Notification" is a message generated by a "Notification Agent" in Ceilometer + based on an "event" and is delivered to the "Collectors" in Ceilometer that + store those notifications (as "sample") to the Ceilometer "Databases". + +Instance State Notification (Ceilometer) [*]_ +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The Doctor project is planning to handle "events" and "notifications" regarding +Resource Status; Instance State, Port State, Host State, etc. Currently, +Ceilometer already receives "events" to identify the state of those resources, +but it does not handle and store them yet. This is why we also need a new event +definition to capture those resource states from "events" created by other +services. + +This BP proposes to add a new compute notification state to handle events from +an instance (server) from nova. It also creates a new meter "instance.state" in +OpenStack. + +.. [*] https://etherpad.opnfv.org/p/doctor_bps + +Event Publisher for Alarm (Ceilometer) [*]_ +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +**Problem statement:** + + The existing "Alarm Evaluator" in OpenStack Ceilometer is periodically + querying/polling the databases in order to check all alarms independently from + other processes. This is adding additional delay to the fault notification + send to the Consumer, whereas one requirement of Doctor is to react on faults + as fast as possible. + + The existing message flow is shown in :numref:`figure12`: after receiving + an "event", a "notification agent" (i.e. "event publisher") will send a + "notification" to a "Collector". The "collector" is collecting the + notifications and is updating the Ceilometer "Meter" database that is storing + information about the "sample" which is capured from original "event". The + "Alarm Evaluator" is periodically polling this databases then querying "Meter" + database based on each alarm configuration. + + In the current Ceilometer implementation, there is no possibility to directly + trigger the "Alarm Evaluator" when a new "event" was received, but the "Alarm + Evaluator" will only find out that requires firing new notification to the + Consumer when polling the database. + +**Change/feature request:** + + This BP proposes to add a new "event publisher for alarm", which is bypassing + several steps in Ceilometer in order to avoid the polling-based approach of + the existing Alarm Evaluator that makes notification slow to users. + + After receiving an "(alarm) event" by listening on the Ceilometer message + queue ("notification bus"), the new "event publisher for alarm" immediately + hands a "notification" about this event to a new Ceilometer component + "Notification-driven alarm evaluator" proposed in the other BP (see Section + 5.6.3). + + Note, the term "publisher" refers to an entity in the Ceilometer architecture + (it is a "notification agent"). It offers the capability to provide + notifications to other services outside of Ceilometer, but it is also used to + deliver notifications to other Ceilometer components (e.g. the "Collectors") + via the Ceilometer "notification bus". + +**Implementation detail** + + * "Event publisher for alarm" is part of Ceilometer + * The standard AMQP message queue is used with a new topic string. + * No new interfaces have to be added to Ceilometer. + * "Event publisher for Alarm" can be configured by the Administrator of + Ceilometer to be used as "Notification Agent" in addition to the existing + "Notifier" + * Existing alarm mechanisms of Ceilometer can be used allowing users to + configure how to distribute the "notifications" transformed from "events", + e.g. there is an option whether an ongoing alarm is re-issued or not + ("repeat_actions"). + +.. [*] https://etherpad.opnfv.org/p/doctor_bps + +Notification-driven alarm evaluator (Ceilometer) [*]_ +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +**Problem statement:** + +The existing "Alarm Evaluator" in OpenStack Ceilometer is periodically +querying/polling the databases in order to check all alarms independently from +other processes. This is adding additional delay to the fault notification send +to the Consumer, whereas one requirement of Doctor is to react on faults as fast +as possible. + +**Change/feature request:** + +This BP is proposing to add an alternative "Notification-driven Alarm Evaluator" +for Ceilometer that is receiving "notifications" sent by the "Event Publisher +for Alarm" described in the other BP. Once this new "Notification-driven Alarm +Evaluator" received "notification", it finds the "alarm" configurations which +may relate to the "notification" by querying the "alarm" database with some keys +i.e. resource ID, then it will evaluate each alarm with the information in that +"notification". + +After the alarm evaluation, it will perform the same way as the existing "alarm +evaluator" does for firing alarm notification to the Consumer. Similar to the +existing Alarm Evaluator, this new "Notification-driven Alarm Evaluator" is +aggregating and correlating different alarms which are then provided northbound +to the Consumer via the OpenStack "Alarm Notifier". The user/administrator can +register the alarm configuration via existing Ceilometer API [*]_. Thereby, he +can configure whether to set an alarm or not and where to send the alarms to. + +**Implementation detail** + +* The new "Notification-driven Alarm Evaluator" is part of Ceilometer. +* Most of the existing source code of the "Alarm Evaluator" can be re-used to + implement this BP +* No additional application logic is needed +* It will access the Ceilometer Databases just like the existing "Alarm + evaluator" +* Only the polling-based approach will be replaced by a listener for + "notifications" provided by the "Event Publisher for Alarm" on the Ceilometer + "notification bus". +* No new interfaces have to be added to Ceilometer. + + +.. [*] https://etherpad.opnfv.org/p/doctor_bps +.. [*] https://wiki.openstack.org/wiki/Ceilometer/Alerting + +Report host fault to update server state immediately (Nova) [*]_ +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +**Problem statement:** + +* Nova state change for failed or unreachable host is slow and does not reliably + state host is down or not. This might cause same server instance to run twice + if action taken to evacuate instance to another host. +* Nova state for server(s) on failed host will not change, but remains active + and running. This gives the user false information about server state. +* VIM northbound interface notification of host faults towards VNFM and NFVO + should be in line with OpenStack state. This fault notification is a Telco + requirement defined in ETSI and will be implemented by OPNFV Doctor project. +* Openstack user cannot make HA actions fast and reliably by trusting server + state and host state. + +**Proposed change:** + +There needs to be a new API for Admin to state host is down. This API is used to +mark services running in host down to reflect the real situation. + +Example on compute node is: + +* When compute node is up and running::: + + vm_state: activeand power_state: running + nova-compute state: up status: enabled + +* When compute node goes down and new API is called to state host is down::: + + vm_state: stopped power_state: shutdown + nova-compute state: down status: enabled + +**Alternatives:** + +There is no attractive alternative to detect all different host faults than to +have an external tool to detect different host faults. For this kind of tool to +exist there needs to be new API in Nova to report fault. Currently there must be +some kind of workarounds implemented as cannot trust or get the states from +OpenStack fast enough. + +.. [*] https://blueprints.launchpad.net/nova/+spec/update-server-state-immediately + +Other related BPs +^^^^^^^^^^^^^^^^^ + +This section lists some BPs related to Doctor, but proposed by drafters outside +the OPNFV community. + +pacemaker-servicegroup-driver [*]_ +__________________________________ + +This BP will detect and report host down quite fast to OpenStack. This however +might not work properly for example when management network has some problem and +host reported faulty while VM still running there. This might lead to launching +same VM instance twice causing problems. Also NB IF message needs fault reason +and for that the source needs to be a tool that detects different kind of faults +as Doctor will be doing. Also this BP might need enhancement to change server +and service states correctly. + +.. [*] https://blueprints.launchpad.net/nova/+spec/pacemaker-servicegroup-driver diff --git a/docs/development/requirements/06-summary.rst b/docs/development/requirements/06-summary.rst new file mode 100644 index 00000000..61bf3f47 --- /dev/null +++ b/docs/development/requirements/06-summary.rst @@ -0,0 +1,24 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +Summary and conclusion +====================== + +The Doctor project aimed at detailing NFVI fault management and NFVI maintenance +requirements. These are indispensable operations for an Operator, and extremely +necessary to realize telco-grade high availability. High availability is a large +topic; the objective of Doctor is not to realize a complete high availability +architecture and implementation. Instead, Doctor limited itself to addressing +the fault events in NFVI, and proposes enhancements necessary in VIM, e.g. +OpenStack, to ensure VNFs availability in such fault events, taking a Telco VNFs +application level management system into account. + +The Doctor project performed a robust analysis of the requirements from NFVI +fault management and NFVI maintenance operation, concretely found out gaps in +between such requirements and the current implementation of OpenStack, and +proposed potential development plans to fill out such gaps in OpenStack. +Blueprints are already under investigation and the next step is to fill out +those gaps in OpenStack by code development in the coming releases. + +.. + vim: set tabstop=4 expandtab textwidth=80: diff --git a/docs/development/requirements/07-annex.rst b/docs/development/requirements/07-annex.rst new file mode 100644 index 00000000..c3a7899d --- /dev/null +++ b/docs/development/requirements/07-annex.rst @@ -0,0 +1,129 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +.. _nfvi_faults: + +Annex: NFVI Faults +================================================= + +Faults in the listed elements need to be immediately notified to the Consumer in +order to perform an immediate action like live migration or switch to a hot +standby entity. In addition, the Administrator of the host should trigger a +maintenance action to, e.g., reboot the server or replace a defective hardware +element. + +Faults can be of different severity, i.e., critical, warning, or +info. Critical faults require immediate action as a severe degradation of the +system has happened or is expected. Warnings indicate that the system +performance is going down: related actions include closer (e.g. more frequent) +monitoring of that part of the system or preparation for a cold migration to a +backup VM. Info messages do not require any action. We also consider a type +"maintenance", which is no real fault, but may trigger maintenance actions +like a re-boot of the server or replacement of a faulty, but redundant HW. + +Faults can be gathered by, e.g., enabling SNMP and installing some open source +tools to catch and poll SNMP. When using for example Zabbix one can also put an +agent running on the hosts to catch any other fault. In any case of failure, the +Administrator should be notified. The following tables provide a list of high +level faults that are considered within the scope of the Doctor project +requiring immediate action by the Consumer. + +**Compute/Storage** + ++-------------------+----------+------------+-----------------+------------------+ +| Fault | Severity | How to | Comment | Immediate action | +| | | detect? | | to recover | ++===================+==========+============+=================+==================+ +| Processor/CPU | Critical | Zabbix | | Switch to hot | +| failure, CPU | | | | standby | +| condition not ok | | | | | ++-------------------+----------+------------+-----------------+------------------+ +| Memory failure/ | Critical | Zabbix | | Switch to hot | +| Memory condition | | (IPMI) | | standby | +| not ok | | | | | ++-------------------+----------+------------+-----------------+------------------+ +| Network card | Critical | Zabbix/ | | Switch to hot | +| failure, e.g. | | Ceilometer | | standby | +| network adapter | | | | | +| connectivity lost | | | | | ++-------------------+----------+------------+-----------------+------------------+ +| Disk crash | Info | RAID | Network storage | Inform OAM | +| | | monitoring | is very | | +| | | | redundant (e.g. | | +| | | | RAID system) | | +| | | | and can | | +| | | | guarantee high | | +| | | | availability | | ++-------------------+----------+------------+-----------------+------------------+ +| Storage | Critical | Zabbix | | Live migration | +| controller | | (IPMI) | | if storage | +| | | | | is still | +| | | | | accessible; | +| | | | | otherwise hot | +| | | | | standby | ++-------------------+----------+------------+-----------------+------------------+ +| PDU/power | Critical | Zabbix/ | | Switch to hot | +| failure, power | | Ceilometer | | standby | +| off, server reset | | | | | ++-------------------+----------+------------+-----------------+------------------+ +| Power | Warning | SNMP | | Live migration | +| degration, power | | | | | +| redundancy lost, | | | | | +| power threshold | | | | | +| exceeded | | | | | ++-------------------+----------+------------+-----------------+------------------+ +| Chassis problem | Warning | SNMP | | Live migration | +| (e.g. fan | | | | | +| degraded/failed, | | | | | +| chassis power | | | | | +| degraded), CPU | | | | | +| fan problem, | | | | | +| temperature/ | | | | | +| thermal condition | | | | | +| not ok | | | | | ++-------------------+----------+------------+-----------------+------------------+ +| Mainboard failure | Critical | Zabbix | e.g. PCIe, SAS | Switch to hot | +| | | (IPMI) | link failure | standby | ++-------------------+----------+------------+-----------------+------------------+ +| OS crash (e.g. | Critical | Zabbix | | Switch to hot | +| kernel panic) | | | | standby | ++-------------------+----------+------------+-----------------+------------------+ + +**Hypervisor** + ++----------------+----------+------------+-------------+-------------------+ +| Fault | Severity | How to | Comment | Immediate action | +| | | detect? | | to recover | ++================+==========+============+=============+===================+ +| System has | Critical | Zabbix | | Switch to hot | +| restarted | | | | standby | ++----------------+----------+------------+-------------+-------------------+ +| Hypervisor | Warning/ | Zabbix/ | | Evacuation/switch | +| failure | Critical | Ceilometer | | to hot standby | ++----------------+----------+------------+-------------+-------------------+ +| Hypervisor | Warning | Alarming | Zabbix/ | Rebuild VM | +| status not | | service | Ceilometer | | +| retrievable | | | unreachable | | +| after certain | | | | | +| period | | | | | ++----------------+----------+------------+-------------+-------------------+ + +**Network** + ++------------------+----------+---------+----------------+---------------------+ +| Fault | Severity | How to | Comment | Immediate action to | +| | | detect? | | recover | ++==================+==========+=========+================+=====================+ +| SDN/OpenFlow | Critical | Ceilo- | | Switch to | +| switch, | | meter | | hot standby | +| controller | | | | or reconfigure | +| degraded/failed | | | | virtual network | +| | | | | topology | ++------------------+----------+---------+----------------+---------------------+ +| Hardware failure | Warning | SNMP | Redundancy of | Live migration if | +| of physical | | | physical | possible otherwise | +| switch/router | | | infrastructure | evacuation | +| | | | is reduced or | | +| | | | no longer | | +| | | | available | | ++------------------+----------+---------+----------------+---------------------+ diff --git a/docs/development/requirements/99-references.rst b/docs/development/requirements/99-references.rst new file mode 100644 index 00000000..0fd3a36a --- /dev/null +++ b/docs/development/requirements/99-references.rst @@ -0,0 +1,32 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +References and bibliography +=========================== + +.. [DOCT] OPNFV, "Doctor" requirements project, [Online]. Available at + https://wiki.opnfv.org/doctor +.. [PRED] OPNFV, "Data Collection for Failure Prediction" requirements project + [Online]. Available at https://wiki.opnfv.org/prediction +.. [OPSK] OpenStack, [Online]. Available at https://www.openstack.org/ +.. [CEIL] OpenStack Telemetry (Ceilometer), [Online]. Available at + https://wiki.openstack.org/wiki/Ceilometer +.. [NOVA] OpenStack Nova, [Online]. Available at + https://wiki.openstack.org/wiki/Nova +.. [NEUT] OpenStack Neutron, [Online]. Available at + https://wiki.openstack.org/wiki/Neutron +.. [CIND] OpenStack Cinder, [Online]. Available at + https://wiki.openstack.org/wiki/Cinder +.. [MONA] OpenStack Monasca, [Online], Available at + https://wiki.openstack.org/wiki/Monasca +.. [OSAG] OpenStack Cloud Administrator Guide, [Online]. Available at + http://docs.openstack.org/admin-guide-cloud/content/ +.. [ZABB] ZABBIX, the Enterprise-class Monitoring Solution for Everyone, + [Online]. Available at http://www.zabbix.com/ +.. [ENFV] ETSI NFV, [Online]. Available at + http://www.etsi.org/technologies-clusters/technologies/nfv + + + +.. + vim: set tabstop=4 expandtab textwidth=80: diff --git a/docs/development/requirements/glossary.rst b/docs/development/requirements/glossary.rst new file mode 100644 index 00000000..2c82b37f --- /dev/null +++ b/docs/development/requirements/glossary.rst @@ -0,0 +1,89 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +**Definition of terms** + +Different SDOs and communities use different terminology related to +NFV/Cloud/SDN. This list tries to define an OPNFV terminology, +mapping/translating the OPNFV terms to terminology used in other contexts. + + +.. glossary:: + + ACT-STBY configuration + Failover configuration common in Telco deployments. It enables the + operator to use a standby (STBY) instance to take over the functionality + of a failed active (ACT) instance. + + Administrator + Administrator of the system, e.g. OAM in Telco context. + + Consumer + User-side Manager; consumer of the interfaces produced by the VIM; VNFM, + NFVO, or Orchestrator in ETSI NFV [ENFV]_ terminology. + + EPC + Evolved Packet Core, the main component of the core network architecture + of 3GPP's LTE communication standard. + + MME + Mobility Management Entity, an entity in the EPC dedicated to mobility + management. + + NFV + Network Function Virtualization + + NFVI + Network Function Virtualization Infrastructure; totality of all hardware + and software components which build up the environment in which VNFs are + deployed. + + S/P-GW + Serving/PDN-Gateway, two entities in the EPC dedicated to routing user + data packets and providing connectivity from the UE to external packet + data networks (PDN), respectively. + + Physical resource + Actual resources in NFVI; not visible to Consumer. + + VNFM + Virtualized Network Function Manager; functional block that is + responsible for the lifecycle management of VNF. + + NFVO + Network Functions Virtualization Orchestrator; functional block that + manages the Network Service (NS) lifecycle and coordinates the + management of NS lifecycle, VNF lifecycle (supported by the VNFM) and + NFVI resources (supported by the VIM) to ensure an optimized allocation + of the necessary resources and connectivity. + + VIM + Virtualized Infrastructure Manager; functional block that is responsible + for controlling and managing the NFVI compute, storage and network + resources, usually within one operator's Infrastructure Domain, e.g. + NFVI Point of Presence (NFVI-PoP). + + Virtual Machine (VM) + Virtualized computation environment that behaves very much like a + physical computer/server. + + Virtual network + Virtual network routes information among the network interfaces of VM + instances and physical network interfaces, providing the necessary + connectivity. + + Virtual resource + A Virtual Machine (VM), a virtual network, or virtualized storage; + Offered resources to "Consumer" as result of infrastructure + virtualization; visible to Consumer. + + Virtual Storage + Virtualized non-volatile storage allocated to a VM. + + VNF + Virtualized Network Function. Implementation of a Network Function that + can be deployed on a Network Function Virtualization Infrastructure + (NFVI). + +.. + vim: set tabstop=4 expandtab textwidth=80: diff --git a/docs/development/requirements/images/LICENSE b/docs/development/requirements/images/LICENSE new file mode 100644 index 00000000..21a2d03d --- /dev/null +++ b/docs/development/requirements/images/LICENSE @@ -0,0 +1,14 @@ +Copyright 2017 Open Platform for NFV Project, Inc. and its contributors + +Open Platform for NFV Project Documentation License +=================================================== +Any documentation developed by the "Open Platform for NFV Project" +is licensed under a Creative Commons Attribution 4.0 International License. +You should have received a copy of the license along with this. If not, +see . + +Unless required by applicable law or agreed to in writing, documentation +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. diff --git a/docs/development/requirements/images/figure1.png b/docs/development/requirements/images/figure1.png new file mode 100644 index 00000000..267ddddc Binary files /dev/null and b/docs/development/requirements/images/figure1.png differ diff --git a/docs/development/requirements/images/figure10.png b/docs/development/requirements/images/figure10.png new file mode 100755 index 00000000..d3268018 Binary files /dev/null and b/docs/development/requirements/images/figure10.png differ diff --git a/docs/development/requirements/images/figure11.png b/docs/development/requirements/images/figure11.png new file mode 100755 index 00000000..b5fe0f8c Binary files /dev/null and b/docs/development/requirements/images/figure11.png differ diff --git a/docs/development/requirements/images/figure12.png b/docs/development/requirements/images/figure12.png new file mode 100755 index 00000000..2d394629 Binary files /dev/null and b/docs/development/requirements/images/figure12.png differ diff --git a/docs/development/requirements/images/figure13.png b/docs/development/requirements/images/figure13.png new file mode 100755 index 00000000..5f8227a5 Binary files /dev/null and b/docs/development/requirements/images/figure13.png differ diff --git a/docs/development/requirements/images/figure14.png b/docs/development/requirements/images/figure14.png new file mode 100755 index 00000000..b65ca9ae Binary files /dev/null and b/docs/development/requirements/images/figure14.png differ diff --git a/docs/development/requirements/images/figure2.png b/docs/development/requirements/images/figure2.png new file mode 100644 index 00000000..9a3b166d Binary files /dev/null and b/docs/development/requirements/images/figure2.png differ diff --git a/docs/development/requirements/images/figure3.png b/docs/development/requirements/images/figure3.png new file mode 100755 index 00000000..ee04dfae Binary files /dev/null and b/docs/development/requirements/images/figure3.png differ diff --git a/docs/development/requirements/images/figure4.png b/docs/development/requirements/images/figure4.png new file mode 100755 index 00000000..9eff177a Binary files /dev/null and b/docs/development/requirements/images/figure4.png differ diff --git a/docs/development/requirements/images/figure5a.png b/docs/development/requirements/images/figure5a.png new file mode 100755 index 00000000..d347b412 Binary files /dev/null and b/docs/development/requirements/images/figure5a.png differ diff --git a/docs/development/requirements/images/figure5b.png b/docs/development/requirements/images/figure5b.png new file mode 100755 index 00000000..75a43669 Binary files /dev/null and b/docs/development/requirements/images/figure5b.png differ diff --git a/docs/development/requirements/images/figure5c.png b/docs/development/requirements/images/figure5c.png new file mode 100755 index 00000000..4fb2ba03 Binary files /dev/null and b/docs/development/requirements/images/figure5c.png differ diff --git a/docs/development/requirements/images/figure6.png b/docs/development/requirements/images/figure6.png new file mode 100755 index 00000000..cf0d2be9 Binary files /dev/null and b/docs/development/requirements/images/figure6.png differ diff --git a/docs/development/requirements/images/figure7.png b/docs/development/requirements/images/figure7.png new file mode 100755 index 00000000..b88a2e65 Binary files /dev/null and b/docs/development/requirements/images/figure7.png differ diff --git a/docs/development/requirements/images/figure8.png b/docs/development/requirements/images/figure8.png new file mode 100755 index 00000000..907a0b30 Binary files /dev/null and b/docs/development/requirements/images/figure8.png differ diff --git a/docs/development/requirements/images/figure9.png b/docs/development/requirements/images/figure9.png new file mode 100755 index 00000000..61501c4d Binary files /dev/null and b/docs/development/requirements/images/figure9.png differ diff --git a/docs/development/requirements/index.rst b/docs/development/requirements/index.rst new file mode 100644 index 00000000..fcbfb88e --- /dev/null +++ b/docs/development/requirements/index.rst @@ -0,0 +1,62 @@ +.. This work is licensed under a Creative Commons Attribution 4.0 International License. +.. http://creativecommons.org/licenses/by/4.0 + +**************************************** +Doctor: Fault Management and Maintenance +**************************************** + +:Project: Doctor, https://wiki.opnfv.org/doctor +:Editors: Ashiq Khan (NTT DOCOMO), Gerald Kunzmann (NTT DOCOMO) +:Authors: Ryota Mibu (NEC), Carlos Goncalves (NEC), Tomi Juvonen (Nokia), + Tommy Lindgren (Ericsson), Bertrand Souville (NTT DOCOMO), + Balazs Gibizer (Ericsson), Ildiko Vancsa (Ericsson) and others. + +:Abstract: Doctor is an OPNFV requirement project [DOCT]_. Its scope is NFVI + fault management, and maintenance and it aims at developing and + realizing the consequent implementation for the OPNFV reference + platform. + + This deliverable is introducing the use cases and operational + scenarios for Fault Management considered in the Doctor project. + From the general features, a high level architecture describing + logical building blocks and interfaces is derived. Finally, + a detailed implementation is introduced, based on available open + source components, and a related gap analysis is done as part of + this project. The implementation plan finally discusses an initial + realization for a NFVI fault management and maintenance solution in + open source software. + +:History: + + ========== ===================================================== + Date Description + ========== ===================================================== + 02.12.2014 Project creation + 14.04.2015 Initial version of the deliverable uploaded to Gerrit + 18.05.2015 Stable version of the Doctor deliverable + 25.02.2016 Updated version for the Brahmaputra release + 26.09.2016 Updated version for the Colorado release + xx.xx.2017 Updated version for the Danube release + ========== ===================================================== + +.. raw:: latex + + \newpage + +.. include:: + glossary.rst + +.. toctree:: + :maxdepth: 4 + :numbered: + + 01-intro.rst + 02-use_cases.rst + 03-architecture.rst + 04-gaps.rst + 05-implementation.rst + 06-summary.rst + 07-annex.rst + +.. include:: + 99-references.rst -- cgit 1.2.3-korg