/healthz logs errors

[davidkarlsen]

Bug Report

What did you do?
call pod:8686/healthz endpoint.
It returns the "ok" payload and everything seems fine. But logs are full of

github-actions-runner-operator-bb98fd99b-m87r6 github-actions-runner-operator {"level":"error","ts":1587974842.2687132,"logger":"kubemetrics","msg":"Unable to write to serve custom metrics","stacktrace":"github.com/go-logr/zapr.(*zapLogger).Error\n\t/home/runner/go/pkg/mod/github.com/go-logr/zapr@v0.1.1/zapr.go:128\ngithub.51.al/operator-framework/operator-sdk/pkg/kube-metrics.ServeMetrics.func1\n\t/home/runner/go/pkg/mod/github.com/operator-framework/operator-sdk@v0.17.0/pkg/kube-metrics/server.go:39\nnet/http.HandlerFunc.ServeHTTP\n\t/opt/hostedtoolcache/go/1.13.10/x64/src/net/http/server.go:2007\nnet/http.(*ServeMux).ServeHTTP\n\t/opt/hostedtoolcache/go/1.13.10/x64/src/net/http/server.go:2387\nnet/http.serverHandler.ServeHTTP\n\t/opt/hostedtoolcache/go/1.13.10/x64/src/net/http/server.go:2802\nnet/http.(*conn).serve\n\t/opt/hostedtoolcache/go/1.13.10/x64/src/net/http/server.go:1890"}

What did you expect to see?
No log message

What did you see instead? Under which circumstances?
See above

Environment

• operator-sdk version:
  v0.17.0

• go version:
  1.13.10

• Kubernetes version information:

Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.2", GitCommit:"52c56ce7a8272c798dbc29846288d7cd9fbae032", GitTreeState:"clean", BuildDate:"2020-04-16T23:35:15Z", GoVersion:"go1.14.2", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.9+icp-ee", GitCommit:"fccfecc454d446967475ce34d13d3d63d407bf09", GitTreeState:"clean", BuildDate:"2019-08-27T08:46:50Z", GoVersion:"go1.11.13", Compiler:"gc", Platform:"linux/amd64"}
But it also happens on newer versions.

• Kubernetes cluster kind:
  ** IBM Cloud private
  ** docker for desktop

• Are you writing your operator in ansible, helm, or go?
  go

Additional context
code:
https://github.com/evryfs/github-actions-runner-operator/

[camilamacedo86]

HI @davidkarlsen,

Your error came from :

        mux.HandleFunc(healthzPath, func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(200)
		_, err := w.Write([]byte("ok"))
		log.Error(err, "Unable to write to serve custom metrics")
	})

ref.: https://github.com/operator-framework/operator-sdk/blob/master/pkg/kube-metrics/server.go#L36-L56

By looking at the code, shows that the error Unable to write to serve custom metrics will be retuned always when the endpoint /healthz is called. @joelanford have you more context over it? Could you give a hand with?

[estroz]

Sounds like we just need to check the error.

[estroz]

/kind bug