[bugfix] fix StatefulsetReady check

[LuyuZhang00]

What type of PR is this?

/kind bug

We noticed that when the pods in the worker StatefulSet (sts) have been created but are not yet ready, the sts is still considered "ready", which doesn't match the expected behavior. We found that the sts has three parameters used to determine its readiness status(/go/pkg/mod/k8s.io/[email protected]/apps/v1/types.go) :

• Replicas: The number of Pods created by the StatefulSet controller. This includes pods in all states (Running, Pending, Unknown, etc.) and does not consider whether the pods are ready or available.
• ReadyReplicas: The number of pods created for this StatefulSet with a Ready Condition. This requires the pods to be in the Running state and for all their containers to have passed the readiness probe.
• AvailableReplicas: Total number of available pods (ready for at least minReadySeconds) targeted by this statefulset. In addition to being "ready" (as defined by ReadyReplicas), the pods must have been running for at least the duration specified by minReadySeconds. The minReadySeconds defaults to 0s, which makes it behave the same as ReadyReplicas. However, when a specific value is set, it provides the Pod with a sufficient stable running time

Based on the current situation, using ReadyReplicas may be a better choice to determine the ready status of a StatefulSet
cc @Edwinhr716 @kerthcet

[netlify]

✅ Deploy Preview for kubernetes-sigs-lws canceled.

Name	Link
🔨 Latest commit	c1a3dac
🔍 Latest deploy log	https://app.netlify.com/projects/kubernetes-sigs-lws/deploys/691e7c70f5333500080f378f

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: LuyuZhang00
Once this PR has been reviewed and has the lgtm label, please assign edwinhr716 for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Hi @LuyuZhang00. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[yankay]

/ok-to-test

[kannon92]

Why would you not choose AvailableReplicas? That seems even better than ReadyReplicas if MinReady is set.