30d5bacb19
This review syncs the state of launchpad with the spec repo for things implemented up to liberty-3. There are no changes to the specs, just things being moved around. Change-Id: I930d33532b268b6e933c8be06a0569c20fd09586
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159 lines
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This work is licensed under a Creative Commons Attribution 3.0 Unported
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License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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==========================================
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Make Resource Tracker Use Objects
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==========================================
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https://blueprints.launchpad.net/nova/+spec/make-resource-tracker-use-objects
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This blueprint was approved for Kilo but some patches missed the feature
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freeze. This proposal is to complete the remaining patches in Liberty.
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Nova is converting data structures it uses to communicate via RPC and through
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the database to use an object encapsulation called Nova Objects. This supports
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of multi-versioning for live-upgrade and database schema independence. This
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blueprint covers the conversion of the resource tracker to use Nova Objects.
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Problem description
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===================
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Conversion to Nova Objects will replace dict data structures that are currently
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communicated via the conductor API with Nova Object versions. Where necessary
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the Nova Objects will be extended to cover parameters that are not already
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implemented.
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Use Cases
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---------
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As an operator I want to be able to upgrade Nova without any downtime.
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Project Priority
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----------------
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This blueprint fits under the Live Upgrades priority.
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Proposed change
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===============
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The Nova Object classes that will be used include:
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- ComputeNode
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- Instance
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- Migrations
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- Flavor
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- Service
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- PciDevicePool
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The ComputeNode object was modified during the Kilo cycle to include
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required fields. A small amount of cleanup is needed around the
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PciDevicePool object to correct assignment of tags and the API samples
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and tests associated with the os-pci API. PciDevicePool is used
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in the ComputeNode object so this is required before finally replacing
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compute node data structures in the resource tracker with the ComputeNode
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object.
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The other objects were added to the resource tracker during Kilo.
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Alternatives
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------------
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None.
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Data model impact
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-----------------
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The objects isolate the code from the database schema. They are written to
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operate with existing data model versions. At present the scheduler does not
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the ComputeNode object, so code there will need to tolerate changes in
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database schema or the format of data stored in fields.
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REST API impact
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---------------
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None. The current tests and API samples for pci stats are incorrect and
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will be fixed. This does not change the relvant API, so although the
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samples change, the API doesn't.
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Security impact
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---------------
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None.
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Notifications impact
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--------------------
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None.
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Other end user impact
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---------------------
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None.
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Performance Impact
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------------------
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None.
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Other deployer impact
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---------------------
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The objects are written to be compatible with the database schema used in
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Juno. There is no database migration associated with the remaining
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changes in this blueprint and the format of data stored in the fields of
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the database will not change. This means that a combination of Kilo and
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Liberty versions of the compute nodes will be able to coexist and interact
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with the scheduler.
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Developer impact
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----------------
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Developers working on the resource tracker will be required to use the new
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objects instead of directly making database calls to conductor.
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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pmurray
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Work Items
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----------
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These are the remaining work items left to complete the blueprint.
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* Use ComputeNode object in resource tracker
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Some of these work items are currently ready for review:
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https://review.openstack.org/#/q/topic:bp/make-resource-tracker-use-objects,n,z
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Dependencies
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============
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None
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Testing
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=======
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This does not affect existing tempest tests. Unit tests will be
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added for each object and existing tests will be modified to deal
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with the new data structure.
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Documentation Impact
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====================
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The os-pci API response samples will be correct. There will be no new feature
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and the APIs will not change, but API samples appear in the documentation so
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this will cause a minor documentation impact.
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References
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==========
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https://blueprints.launchpad.net/nova/+spec/scheduler-lib
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