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https://issues.apache.org/jira/browse/FLINK-41304?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-41304:
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Labels: pull-request-available (was: )
> Support canary resources on FlinkDeployment only
> ------------------------------------------------
>
> Key: FLINK-41304
> URL: https://issues.apache.org/jira/browse/FLINK-41304
> Project: Flink
> Issue Type: Improvement
> Components: Kubernetes Operator
> Reporter: Dennis-Mircea Ciupitu
> Priority: Major
> Labels: pull-request-available
>
> h1. Motivation
> The canary label ({{{}flink.apache.org/canary: "true"{}}}) is handled
> inconsistently across the operator resource kinds:
> * {{FlinkDeployment}} and {{FlinkSessionJob}} canaries are supported and
> checked by the health probe.
> * {{FlinkStateSnapshot}} has no canary handling in its controller, so the
> label is ignored and the resource is reconciled as a regular snapshot. The
> validation webhook still skips every canary-labelled resource, so an invalid
> canary-labelled snapshot is accepted on creation and only rejected later by
> the operator's own validation.
> * {{FlinkBlueGreenDeployment}} has no canary handling either, so the label
> is silently ignored and the resource is reconciled as a regular blue/green
> deployment.
> All controllers share the same reconciliation thread pool, so a single canary
> kind already verifies that the operator picks up and reconciles spec changes
> in time.
> A canary of another kind only adds checks on that kind’s informers and event
> processing, which the operator’s health check mechanism already provides
> regardless of canaries.
> {{FlinkDeployment}} is the central resource of the operator, so canaries only
> need to be supported on that kind.
> h1. Proposal
> To unify the canary approach and limit it to detecting JOSDK reconciliation
> slowdowns:
> * Canary resources are supported on {{FlinkDeployment}} only.
> * {{FlinkSessionJob}} canaries keep working but are deprecated, with a
> warning log, and are planned to be handled like the other kinds in a later
> release.
> * Canary-labelled {{FlinkStateSnapshot}} and {{FlinkBlueGreenDeployment}}
> resources are not reconciled, and a warning explains that canaries must be
> {{FlinkDeployment}} resources.
> * The validation webhook only skips the validation of supported canary kinds.
> * The health documentation is updated accordingly.
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