etcdserver: add learner check to readyz

[gojoy]

fix #19001

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: gojoy
Once this PR has been reviewed and has the lgtm label, please assign serathius for approval. For more information see the Kubernetes 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 @gojoy. Thanks for your PR.

I'm waiting for a etcd-io 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.

[gojoy]

@siyuanfoundation Hi. Can you review this request

[siyuanfoundation]

/ok-to-test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.72%. Comparing base (b531071) to head (f47670b).
Report is 29 commits behind head on main.

Additional details and impacted files

Files with missing lines	Coverage Δ
server/etcdserver/api/etcdhttp/health.go	91.46% <100.00%> (+0.24%)	⬆️

... and 29 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #19086      +/-   ##
==========================================
- Coverage   68.75%   68.72%   -0.04%     
==========================================
  Files         420      420              
  Lines       35640    35646       +6     
==========================================
- Hits        24506    24497       -9     
- Misses       9705     9716      +11     
- Partials     1429     1433       +4     

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b531071...f47670b. Read the comment docs.

[siyuanfoundation]

lgtm overall. Can you fix the tiny error in the verify test?
Thanks!

[gojoy]

/retest-required

[gojoy]

lgtm overall. Can you fix the tiny error in the verify test? Thanks!

done

[gojoy]

lgtm overall. Can you fix the tiny error in the verify test? Thanks!

error in the verify test has been fixed. please review again @siyuanfoundation