34 lines
1.7 KiB
YAML
34 lines
1.7 KiB
YAML
---
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features:
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- |
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Adds a new feature to the ironic virt driver, which allows
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multiple nova-compute services to be run simultaneously. This uses
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consistent hashing to divide the ironic nodes between the nova-compute
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services, with the hash ring being refreshed each time the resource tracker
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runs.
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Note that instances will still be owned by the same nova-compute service
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for the entire life of the instance, and so the ironic node that instance
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is on will also be managed by the same nova-compute service until the node
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is deleted. This also means that removing a nova-compute service will
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leave instances managed by that service orphaned, and as such most
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instance actions will not work until a nova-compute service with the same
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hostname is brought (back) online.
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When nova-compute services are brought up or down, the ring will eventually
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re-balance (when the resource tracker runs on each compute). This may
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result in duplicate compute_node entries for ironic nodes while the
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nova-compute service pool is re-balancing. However, because any
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nova-compute service running the ironic virt driver can manage any ironic
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node, if a build request goes to the compute service not currently managing
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the node the build request is for, it will still succeed.
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There is no configuration to do to enable this feature; it is always
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enabled. There are no major changes when only one compute service is
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running. If more compute services are brought online, the bigger changes
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come into play.
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Note that this is tested when running with only one nova-compute service,
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but not more than one. As such, this should be used with caution for
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multiple compute hosts until it is properly tested in CI.
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