Make linkerd mc link's output compatible with pre-edge-24.9.3 clusters
#13161
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Followup to #1306 ## Problem if we run `linkerd mc link` using the latest CLI and attempted to apply the resulting manifests into a cluster with linkerd-multicluster on version edge-24.9.2 and earlier we would get the following error: ``` Error from server (BadRequest): error when creating "STDIN": Link in version "v1alpha1" cannot be handled as a Link: strict decoding error: unknown field "spec.probeSpec.failureThreshold", unknown field "spec.probeSpec.timeout" ``` ## Solution This changes the `linkerd mc link` command so that it doesn't generate default entries for the new (optional) fields `failureThreshold` and `timeout`, so that the output remains compatible with previous versions of the Link CRD. `linkerd mc link` will however still generate those fields for clusters that have an up-to-date multicluster extension. Those fields values continue to be retrieved from the gateway service's `mirror.linkerd.io/probe-failure-threshold` and `mirror.linkerd.io/probe-timeout` annotations. Note that once the linkerd-multicluster extension gets upgraded in the cluster to match the CLI version, the existing Link CRs will automatically receive the default values for these fields.
adleong
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Do we need to move this defaulting into the read side i.e. in ProbeWorker?
What happens when a ProbeWorker reads a Link with no Timeout or no FailureThresold?
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Attempting to answer my own question.... when the mc extension is upgraded, the Link CRD is also upgraded, and Links will receive default values for the new fields from the CRD schema? So a new ProbeWorker should always see these fields populated in a Link resource (either explicitly or from the Link CRD schema default). Is that correct? |
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That is correct. Given the manifests for the Link CRD and the service mirror workload are produced by the same command ( |
…rresponding annotations from the gateway workload
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To still provide compatibility of the latest |
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Followup to #13061
Problem
if we run
linkerd mc linkusing the latest CLI and attempted to apply the resulting manifests into a cluster with linkerd-multicluster on version edge-24.9.2 and earlier we would get the following error:Solution
This changes the
linkerd mc linkcommand so that it doesn't generate default entries for the new (optional) fieldsfailureThresholdandtimeout, so that the output remains compatible with previous versions of the Link CRD.linkerd mc linkwill however still generate those fields for clusters that have an up-to-date multicluster extension. Those fields values continue to be retrieved from the gateway service'smirror.linkerd.io/probe-failure-thresholdandmirror.linkerd.io/probe-timeoutannotations.We're also removing those fields from the linkerd-multicluster values.yaml file, and we're removing the corresponding annotations on the gateway workload. These values and annotations were added in edge-24.9.3.
This means that (at least for now)
linkerd mc linkwill never generate those fields, and the way for users to tweak them is directly in the Link CR (once the user upgrades the linkerd-multicluster extension, the existing Link CRs will automatically receive the default values, as they are declared in the Link CRD definition).