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diff --git a/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst b/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst index e3aee4d..0a0a746 100644 --- a/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst +++ b/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst @@ -15,9 +15,9 @@ Overview :abstract: This document presents a PROPOSAL for a set of new optional capabilities where the OpenStack Cloud messages into the Guest VMs in order to provide improved Availability - of the hosted VMs. The initial set of new capabilities - include: enabling the detection of and recovery from internal - VM faults and providing a simple out-of-band messaging service + of the hosted VMs. The initial set of new capabilities + include: enabling the detection of and recovery from internal + VM faults and providing a simple out-of-band messaging service to prevent scenarios such as split brain. @@ -44,13 +44,13 @@ Introduction Interfaces / APIs which are built on a messaging service between the OpenStack Host and the Guest VM that uses a simple low-bandwidth datagram messaging capability in the hypervisor and therefore has no - requirements on OpenStack Networking, and is available very early + requirements on OpenStack Networking, and is available very early after spawning the VM. For each capability, the document outlines the interaction with the Guest VM, any key technologies involved, the integration into - the larger OpenStack and OPNFV Architectures (e.g. interactions - with VNFM), specific OPNFV HA Team deliverables, and the use cases + the larger OpenStack and OPNFV Architectures (e.g. interactions + with VNFM), specific OPNFV HA Team deliverables, and the use cases for how availability of the hosted VM is improved. The intent is for the OPNFV HA Team to review the proposals of this @@ -101,9 +101,9 @@ VM Heartbeating and Health Checking VM Heartbeating and Health Checking provides a heartbeat service to monitor the health of guest application(s) within a VM running under the OpenStack Cloud. Loss of heartbeat or a failed health check status will result in a - fault event being reported to OPNFV's DOCTOR infrastructure for alarm - identification, impact analysis and reporting. This would then enable VNF - Managers (VNFMs) listening to OPNFV's DOCTOR External Alarm Reporting through + fault event being reported to OPNFV's DOCTOR infrastructure for alarm + identification, impact analysis and reporting. This would then enable VNF + Managers (VNFMs) listening to OPNFV's DOCTOR External Alarm Reporting through Telemetry's AODH, to initiate any required fault recovery actions. .. image:: OPNFV_HA_Guest_APIs-Overview_HLD-Guest_Heartbeat-FIGURE-1.png @@ -116,14 +116,14 @@ VM Heartbeating and Health Checking A daemon within the Guest VM will register with the OpenStack Guest Heartbeat Service on the compute node to initiate the heartbeating on itself - (i.e. the Guest VM). The OpenStack Compute Node will start heartbeating the - Guest VM, and if the heartbeat fails, the OpenStack Compute Node will report + (i.e. the Guest VM). The OpenStack Compute Node will start heartbeating the + Guest VM, and if the heartbeat fails, the OpenStack Compute Node will report the VM Fault thru DOCTOR and ultimately VNFM will see this thru NOVA VM State Chagne Notifications thru AODH. I.e. VNFM wouild see the VM Heartbeat Failure events in teh same way it sees all other VM Faults, thru DOCTOR initiated VM state changes. - Part of the Guest VM's registration process is the specification of the + Part of the Guest VM's registration process is the specification of the heartbeat interval in msecs. I.e. the registering Guest VM specifies the heartbeating interval. @@ -152,34 +152,34 @@ VM Heartbeating and Health Checking In summary, the deliverables of this activity would be: - - Host Deliverables: (OpenStack and OPNFV blueprints and implementation) + - Host Deliverables: (OpenStack and OPNFV blueprints and implementation) - + an OpenStack Nova or libvirt extension to interpret the new flavor extraspec and - if present setup the required 'virtio serial device' for Host-to-Guest - heartbeat / health-check messaging, on the QEMU/KVM instance created - for the VM, - + an OPNFV Base Host-to-Guest Msging Layer Agent for multiplexing of Application - Layer messaging over the 'virtio serial device' to the VM, - + an OPNFV Heartbeat / Health-Check Compute Agent for local heartbeating of VM - and reporting of failures to the OpenStack Controller, - + an OPNFV Heartbeat / Health-check Server on the OpenStack Controller for - receiving VM failure notifications and reporting these to Vitrage thru - Vitrage's Data Source API, + + an OpenStack Nova or libvirt extension to interpret the new flavor extraspec and + if present setup the required 'virtio serial device' for Host-to-Guest + heartbeat / health-check messaging, on the QEMU/KVM instance created + for the VM, + + an OPNFV Base Host-to-Guest Msging Layer Agent for multiplexing of Application + Layer messaging over the 'virtio serial device' to the VM, + + an OPNFV Heartbeat / Health-Check Compute Agent for local heartbeating of VM + and reporting of failures to the OpenStack Controller, + + an OPNFV Heartbeat / Health-check Server on the OpenStack Controller for + receiving VM failure notifications and reporting these to Vitrage thru + Vitrage's Data Source API, - - Guest Deliverables: + - Guest Deliverables: - + a Heartbeat / Health-Check Message Specification covering - - - Heartbeat / Health-Check Application Layer JSON Protocol, - - Base Host-to-Guest JSON Protocol, - - Details on the use of the underlying 'virtio serial device', + + a Heartbeat / Health-Check Message Specification covering + + - Heartbeat / Health-Check Application Layer JSON Protocol, + - Base Host-to-Guest JSON Protocol, + - Details on the use of the underlying 'virtio serial device', - + a Reference Implementation of the Guest-side support of - Heartbeat / Health-check containing the peer protocol layers - within the Guest. + + a Reference Implementation of the Guest-side support of + Heartbeat / Health-check containing the peer protocol layers + within the Guest. - - will provide code and compile instructions, - - Guest will compile based on its specific OS. + - will provide code and compile instructions, + - Guest will compile based on its specific OS. This proposal requires review with OPNFV's Doctor and Management & Orchestration teams, and OpenStack's Nova Team. @@ -197,7 +197,7 @@ VM Peer State Notification and Messaging NOTE: A Server Group here is the OpenStack Nova Server Group concept where VMs are grouped together for purposes of scheduling. E.g. A specific Server Group - instance can specify whether the VMs within the group should be scheduled to + instance can specify whether the VMs within the group should be scheduled to run on the same compute host or different compute hosts. A 'peer' VM in the context of this section refers to a VM within the same Nova Server Group. @@ -234,32 +234,32 @@ VM Peer State Notification and Messaging In summary, the deliverables for Server Group Messaging would be: - - Host Deliverables: - - + a Nova or libvirt extension to interpret the new flavor extraspec and - if present setup the required 'virtio serial device' for Host-to-Guest - Server Group Messaging, on the QEMU/KVM instance created - for the VM, - + [ leveraging the Base Host-to-Guest Msging Layer Agent from previous section ], - + a Server Group Messaging Compute Agent for implementing the Application Layer - Server Group Messaging JSON Protocol with the VM, and forwarding the - messages to/from the Server Group Messaging Server on the Controller, - + a Server Group Messaging Server on the Controller for routing broadcast - messages to the proper Computes and VMs, as well as listening for Nova - VM State Change Notifications and forwarding these to applicable Computes - and VMs, - - - Guest Deliverables: - - + a Server Group Messaging Message Specification covering - - - Server Group Messaging Application Layer JSON Protocol, - - [ leveraging Base Host-to-Guest JSON Protocol from previous section ], - - [ leveraging Details on the use of the underlying 'virtio serial device' from previous section ], - - + a Reference Implementation of the Guest-side support of - Server Group Messaging containing the peer protocol layers - and Guest Application hooks within the Guest. + - Host Deliverables: + + + a Nova or libvirt extension to interpret the new flavor extraspec and + if present setup the required 'virtio serial device' for Host-to-Guest + Server Group Messaging, on the QEMU/KVM instance created + for the VM, + + [ leveraging the Base Host-to-Guest Msging Layer Agent from previous section ], + + a Server Group Messaging Compute Agent for implementing the Application Layer + Server Group Messaging JSON Protocol with the VM, and forwarding the + messages to/from the Server Group Messaging Server on the Controller, + + a Server Group Messaging Server on the Controller for routing broadcast + messages to the proper Computes and VMs, as well as listening for Nova + VM State Change Notifications and forwarding these to applicable Computes + and VMs, + + - Guest Deliverables: + + + a Server Group Messaging Message Specification covering + + - Server Group Messaging Application Layer JSON Protocol, + - [ leveraging Base Host-to-Guest JSON Protocol from previous section ], + - [ leveraging Details on the use of the underlying 'virtio serial device' from previous section ], + + + a Reference Implementation of the Guest-side support of + Server Group Messaging containing the peer protocol layers + and Guest Application hooks within the Guest. This proposal requires review with OPNFV's Management & Orchestration team and OpenStack's Nova Team. @@ -271,9 +271,9 @@ Conclusion The PROPOSAL of Reach-thru Guest Monitoring and Services described in this document leverage Host-to-Guest messaging to provide a number of extended capabilities that improve the Availability of the hosted VMs. These new capabilities - enable detection of and recovery from internal VM faults and provides a simple + enable detection of and recovery from internal VM faults and provides a simple out-of-band messaging service to prevent scenarios such as split brain. The integration of these proposed new capabilities into the larger OpenStack and OPNFV - Architectures need to be reviewed with the other related teams in OPNFV (Doctor and + Architectures need to be reviewed with the other related teams in OPNFV (Doctor and Management & Orchestration (MANO)) and OpenStack (Nova). diff --git a/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst.bak b/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst.bak new file mode 100644 index 0000000..ad66dac --- /dev/null +++ b/docs/development/overview/OPNFV_HA_Guest_APIs-Overview_HLD.rst.bak @@ -0,0 +1,279 @@ +========================================================================= +PROPOSAL: Reach-thru Guest Monitoring and Services for High Availability +========================================================================= +-------- +Overview +-------- + +:author: Greg Waines +:organization: Wind River Systems +:organization: OPNFV - High Availability +:status: Draft - PROPOSAL +:date: March 2017 +:revision: 1.5 + +:abstract: This document presents a PROPOSAL for a set of new + optional capabilities where the OpenStack Cloud messages + into the Guest VMs in order to provide improved Availability + of the hosted VMs. The initial set of new capabilities + include: enabling the detection of and recovery from internal + VM faults and providing a simple out-of-band messaging service + to prevent scenarios such as split brain. + + +.. sectnum:: + +.. contents:: Table of Contents + + + +Introduction +============ + + This document provides an overview and rationale for a PROPOSAL + of a set of new capabilities where the OpenStack Cloud messages + into the Guest VMs in order to provide improved Availability + of the hosted VMs. + + The initial set of new capabilities specifically include: + + - VM Heartbeating and Health Checking + - VM Peer State Notification and Messaging + + All of these capabilities leverage Host-to-Guest Messaging + Interfaces / APIs which are built on a messaging service between the + OpenStack Host and the Guest VM that uses a simple low-bandwidth + datagram messaging capability in the hypervisor and therefore has no + requirements on OpenStack Networking, and is available very early + after spawning the VM. + + For each capability, the document outlines the interaction with + the Guest VM, any key technologies involved, the integration into + the larger OpenStack and OPNFV Architectures (e.g. interactions + with VNFM), specific OPNFV HA Team deliverables, and the use cases + for how availability of the hosted VM is improved. + + The intent is for the OPNFV HA Team to review the proposals of this + document with the related other teams in OPNFV (Doctor and Management + & Orchestration (MANO)) and OpenStack (Nova). + + + + +Messaging Layer +=============== + + The Host-to-Guest messaging APIs used by the services discussed + in this document use a JSON-formatted application messaging layer + on top of a ‘virtio serial device’ between QEMU on the OpenStack Host + and the Guest VM. JSON formatting provides a simple, humanly readable + messaging format which can be easily parsed and formatted using any + high level programming language being used in the Guest VM (e.g. C/C++, + Python, Java, etc.). Use of the ‘virtio serial device’ provides a + simple, direct communication channel between host and guest which is + independent of the Guest’s L2/L3 networking. + + The upper layer JSON messaging format is actually structured as a + hierarchical JSON format containing a Base JSON Message Layer and an + Application JSON Message Layer: + + - the Base Layer provides the ability to multiplex different groups + of message types on top of a single ‘virtio serial device’ + e.g. + + + heartbeating and healthchecks, + + server group messaging, + + and + + - the Application Layer provides the specific message types and + fields of a particular group of message types. + + + +VM Heartbeating and Health Checking +=================================== + + Normally OpenStack monitoring of the health of a Guest VM is limited + to a black-box approach of simply monitoring the presence of the + QEMU/KVM PID containing the VM. + + VM Heartbeating and Health Checking provides a heartbeat service to monitor + the health of guest application(s) within a VM running under the OpenStack + Cloud. Loss of heartbeat or a failed health check status will result in a + fault event being reported to OPNFV's DOCTOR infrastructure for alarm + identification, impact analysis and reporting. This would then enable VNF + Managers (VNFMs) listening to OPNFV's DOCTOR External Alarm Reporting through + Telemetry's AODH, to initiate any required fault recovery actions. + + .. image:: OPNFV_HA_Guest_APIs-Overview_HLD-Guest_Heartbeat-FIGURE-1.png + + The VM Heartbeating and Health Checking functionality is enabled on + a VM through a new flavor extraspec indicating that the VM supports + and wants to enable Guest Heartbeating. An extension to Nova Compute uses + this extraspec to setup the required 'virtio serial device' for Host-to-Guest + messaging, on the QEMU/KVM instance created for the VM. + + A daemon within the Guest VM will register with the OpenStack Guest + Heartbeat Service on the compute node to initiate the heartbeating on itself + (i.e. the Guest VM). The OpenStack Compute Node will start heartbeating the + Guest VM, and if the heartbeat fails, the OpenStack Compute Node will report + the VM Fault thru DOCTOR and ultimately VNFM will see this thru NOVA VM + State Chagne Notifications thru AODH. I.e. VNFM wouild see the VM Heartbeat + Failure events in teh same way it sees all other VM Faults, thru DOCTOR + initiated VM state changes. + + Part of the Guest VM's registration process is the specification of the + heartbeat interval in msecs. I.e. the registering Guest VM specifies the + heartbeating interval. + + Guest heartbeat works on a challenge response model. The OpenStack + Guest Heartbeat Service on the compute node will challenge the registered + Guest VM daemon with a message each interval. The registered Guest VM daemon + must respond prior to the next interval with a message indicating good health. + If the OpenStack Host does not receive a valid response, or if the response + specifies that the VM is in ill health, then a fault event for the Guest VM + is reported to the OpenStack Guest Heartbeat Service on the controller node which + will report the event to OPNFV's DOCTOR (i.e. thru the OpenStack Vitrage data + source APIs). + + The registered Guest VM daemon's response to the challenge can be as simple + as just immediately responding with OK. This alone allows for detection of + a failed or hung QEMU/KVM instance, or a failure of the OS within the VM to + schedule the registered Guest VM's daemon or failure to route basic IO within + the Guest VM. + + However the registered Guest VM daemon's response to the challenge can be more + complex, running anything from a quick simple sanity check of the health of + applications running in the Guest VM, to a more thorough audit of the + application state and data. In either case returning the status of the + health check enables the OpenStack host to detect and report the event in order + to initiate recovery from application level errors or failures within the Guest VM. + + In summary, the deliverables of this activity would be: + + - Host Deliverables: (OpenStack and OPNFV blueprints and implementation) + + + an OpenStack Nova or libvirt extension to interpret the new flavor extraspec and + if present setup the required 'virtio serial device' for Host-to-Guest + heartbeat / health-check messaging, on the QEMU/KVM instance created + for the VM, + + an OPNFV Base Host-to-Guest Msging Layer Agent for multiplexing of Application + Layer messaging over the 'virtio serial device' to the VM, + + an OPNFV Heartbeat / Health-Check Compute Agent for local heartbeating of VM + and reporting of failures to the OpenStack Controller, + + an OPNFV Heartbeat / Health-check Server on the OpenStack Controller for + receiving VM failure notifications and reporting these to Vitrage thru + Vitrage's Data Source API, + + - Guest Deliverables: + + + a Heartbeat / Health-Check Message Specification covering + + - Heartbeat / Health-Check Application Layer JSON Protocol, + - Base Host-to-Guest JSON Protocol, + - Details on the use of the underlying 'virtio serial device', + + + a Reference Implementation of the Guest-side support of + Heartbeat / Health-check containing the peer protocol layers + within the Guest. + + - will provide code and compile instructions, + - Guest will compile based on its specific OS. + + This proposal requires review with OPNFV's Doctor and Management & Orchestration + teams, and OpenStack's Nova Team. + + + +VM Peer State Notification and Messaging +======================================== + + Server Group State Notification and Messaging is a service to provide + simple low-bandwidth datagram messaging and notifications for servers that + are part of the same server group. This messaging channel is available + regardless of whether IP networking is functional within the server, and + it requires no knowledge within the server about the other members of the group. + + NOTE: A Server Group here is the OpenStack Nova Server Group concept where VMs + are grouped together for purposes of scheduling. E.g. A specific Server Group + instance can specify whether the VMs within the group should be scheduled to + run on the same compute host or different compute hosts. A 'peer' VM in the + context of this section refers to a VM within the same Nova Server Group. + + This Server Group Messaging service provides three types of messaging: + + - Broadcast: this allows a server to send a datagram (size of up to 3050 bytes) + to all other servers within the server group. + - Notification: this provides servers with information about changes to the + (Nova) state of other servers within the server group. + - Status: this allows a server to query the current (Nova) state of all servers within + the server group (including itself). + + A Server Group Messaging entity on both the controller node and the compute nodes + manage the routing of of VM-to-VM messages through the platform, leveraging Nova + to determine Server Group membership and compute node locations of VMs. The Server + Group Messaging entity on the controller also listens to Nova VM state change notifications + and querys VM state data from Nova, in order to provide the VM query and notification + functionality of this service. + + .. image:: OPNFV_HA_Guest_APIs-Overview_HLD-Peer_Messaging-FIGURE-2.png + + This service is not intended for high bandwidth or low-latency operations. It + is best-effort, not reliable. Applications should do end-to-end acks and + retries if they care about reliability. + + This service provides building block type capabilities for the Guest VMs that + contribute to higher availability of the VMs in the Guest VM Server Group. Notifications + of VM Status changes potentially provide a faster and more accurate notification + of failed peer VMs than traditional peer VM monitoring over Tenant Networks. While + the Broadcast Messaging mechanism provides an out-of-band messaging mechanism to + monitor and control a peer VM under fault conditions; e.g. providing the ability to + avoid potential split brain scenarios between 1:1 VMs when faults in Tenant + Networking occur. + + In summary, the deliverables for Server Group Messaging would be: + + - Host Deliverables: + + + a Nova or libvirt extension to interpret the new flavor extraspec and + if present setup the required 'virtio serial device' for Host-to-Guest + Server Group Messaging, on the QEMU/KVM instance created + for the VM, + + [ leveraging the Base Host-to-Guest Msging Layer Agent from previous section ], + + a Server Group Messaging Compute Agent for implementing the Application Layer + Server Group Messaging JSON Protocol with the VM, and forwarding the + messages to/from the Server Group Messaging Server on the Controller, + + a Server Group Messaging Server on the Controller for routing broadcast + messages to the proper Computes and VMs, as well as listening for Nova + VM State Change Notifications and forwarding these to applicable Computes + and VMs, + + - Guest Deliverables: + + + a Server Group Messaging Message Specification covering + + - Server Group Messaging Application Layer JSON Protocol, + - [ leveraging Base Host-to-Guest JSON Protocol from previous section ], + - [ leveraging Details on the use of the underlying 'virtio serial device' from previous section ], + + + a Reference Implementation of the Guest-side support of + Server Group Messaging containing the peer protocol layers + and Guest Application hooks within the Guest. + + This proposal requires review with OPNFV's Management & Orchestration team and + OpenStack's Nova Team. + + +Conclusion +========== + + The PROPOSAL of Reach-thru Guest Monitoring and Services described in this document + leverage Host-to-Guest messaging to provide a number of extended capabilities + that improve the Availability of the hosted VMs. These new capabilities + enable detection of and recovery from internal VM faults and provides a simple + out-of-band messaging service to prevent scenarios such as split brain. + + The integration of these proposed new capabilities into the larger OpenStack and OPNFV + Architectures need to be reviewed with the other related teams in OPNFV (Doctor and + Management & Orchestration (MANO)) and OpenStack (Nova). |