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-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
-^^^^^^^^^^^^^^^^
-
-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 7a). After reception of such instructions, the VIM is
- executing the requested action in order to empty the physical resources (step
- 7b).
-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/figure9.png
- :name: figure9
- :width: 100%
-
- NFVI maintenance work flow
-
-.. figure:: images/figure10.png
- :name: figure10
- :width: 100%
-
- NFVI Maintenance implementation plan
-
-:numref:`figure10` shows a more detailed message flow (Steps 4 to 6)
-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.
-
-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: identifies a subscription to receive fault or maintenance
- notifications.
-* NotificationID: 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: 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-Pairs): 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]
- - Severity [1] (Integer)
- - EventTime [1] (Datetime)
- - ProbableCause [1]
- - 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.
-
-* PhysicalResourceInfoClass:
-
- - PhysicalResourceID [1] (Identifier)
- - PhysicalResourceState [1] (String)
- - FirmwareVersion [0..1] (String)
- - HypervisorVersion [0..1] (String)
- - ZoneID [0..1] (Identifier)
-
-* 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.
-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.
-
-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
-
-..
- vim: set tabstop=4 expandtab textwidth=80: