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healthchecker: use kube-proxy /livez to avoid scale-down false alerts#1306

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dpacgdm:fix/kube-proxy-livez-scale-down
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healthchecker: use kube-proxy /livez to avoid scale-down false alerts#1306
dpacgdm wants to merge 1 commit into
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dpacgdm:fix/kube-proxy-livez-scale-down

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@dpacgdm dpacgdm commented Jul 9, 2026

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Summary

Cluster Autoscaler marks nodes with ToBeDeletedByClusterAutoscaler during scale-down. kube-proxy /healthz intentionally fails in that case for load-balancer connection draining (KEP-3836), which caused NPD to report kube-proxy as unhealthy and fire unnecessary alerts.

Switch the kube-proxy health check endpoint from /healthz to /livez, which only reflects process health and stays healthy during expected scale-down.

Related issue

#1176

Test plan

  • go test ./pkg/healthchecker/... ./cmd/healthchecker/...
  • Updated endpoint unit tests to expect /livez for kube-proxy

Made with Cursor

@dpacgdm
healthchecker: use kube-proxy /livez to avoid scale-down false alerts
288a3ed 
Cluster Autoscaler marks nodes with ToBeDeletedByClusterAutoscaler during
scale-down. kube-proxy /healthz intentionally fails in that case for LB
connection draining (KEP-3836), which made NPD report kube-proxy as
unhealthy. Switch the kube-proxy probe to /livez, which reflects process
health only.

Signed-off-by: dpacgdm <dpac.gdm@gmail.com>
@kubernetes-prow kubernetes-prow Bot added the cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. label Jul 9, 2026
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kubernetes-prow Bot requested review from klueska and mrunalp July 9, 2026 09:00
@kubernetes-prow kubernetes-prow Bot added the needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. label Jul 9, 2026
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kubernetes-prow Bot commented Jul 9, 2026

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Hi @dpacgdm. Thanks for your PR.

I'm waiting for a kubernetes 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.

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kubernetes-prow Bot commented Jul 9, 2026

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: dpacgdm
Once this PR has been reviewed and has the lgtm label, please assign wangzhen127 for approval. For more information see the Code Review Process.

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@kubernetes-prow kubernetes-prow Bot added the size/S Denotes a PR that changes 10-29 lines, ignoring generated files. label Jul 9, 2026
@dpacgdm dpacgdm mentioned this pull request Jul 9, 2026
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dpacgdm commented Jul 21, 2026

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Friendly ping: this PR is still waiting on /ok-to-test from a kubernetes org member so CI can run. Happy to address any feedback — thanks for taking a look when you have a chance.

hakman
hakman requested changes Jul 22, 2026
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Looks good overall. Small comment nit: /livez still checks dataplane synchronization health, it only excludes node eligibility. Could we adjust the wording accordingly?

Comment thread pkg/healthchecker/types/types.go
kubeProxyHealthCheckEndpoint = fmt.Sprintf("http://%s/healthz", net.JoinHostPort(hostAddress, kubeProxyPort))
// Use /livez for kube-proxy so Cluster Autoscaler scale-down (ToBeDeletedByClusterAutoscaler
// taint) does not make NPD report kube-proxy as unhealthy. /healthz intentionally fails in
// that case for load-balancer connection draining (KEP-3836); /livez only reflects process health.

@hakman hakman Jul 22, 2026

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Suggested change
// that case for load-balancer connection draining (KEP-3836); /livez only reflects process health.
// that case for load-balancer connection draining (KEP-3836); /livez reports kube-proxy
// dataplane health without considering node eligibility.

@hakman

hakman commented Jul 22, 2026

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/ok-to-test

@kubernetes-prow kubernetes-prow Bot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Jul 22, 2026
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@hakman hakman hakman requested changes
@klueska klueska Awaiting requested review from klueska
@mrunalp mrunalp Awaiting requested review from mrunalp

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cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. ok-to-test Indicates a non-member PR verified by an org member that is safe to test. size/S Denotes a PR that changes 10-29 lines, ignoring generated files.

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