add toggle to turn off readiness probes #2004
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Any updates regarding this @FxKu? |
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why not use parallel as the default policy? |
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Addresses: #2003, #1978
Having statefulsets with readiness probes was requested a couple of times in the past. We merged it with #1825. Now they are enabled by default, which turns out to be not the greatest idea when
pod_management_policyis set toordered_ready. What could happen?Imagine a cluster with
pod-0andpod-1where the first instance (replica) is broken (e.g. missing a WAL file to restore, disk full etc.) but the master is doing fine. Now the master pod must be replaced (maintenance or it dies for whatever reason). The first pod is failing the readiness probe blocking the second pod from coming back and restore the former master.Without the readiness probe, it's enough for K8s to see that the first pod is in
Runningstate ignoring the actual state of the cluster member. This helped us in the past that masters could repair themselves.Changing the
pod_management_policyis not as easy as it seems, because the operator does not compare it on sync. This PR will include the policy as well as the readiness probe of the container into the stateful set comparison to trigger a replacement of the stateful set (and rolling update of pods if the probe changes).With
ordered_readybeing the default policy, the readiness probe should be disabled by default although this is a breaking change to v1.8. Therefore, a new toggle is added to keep the existing behavior.