I noticed this today while working on T237643: toolforge: new k8s: figure out metrics / observability:
root@tools-k8s-control-1:~# kubectl logs kube-apiserver-tools-k8s-control-1 -n kube-system [...] I1119 13:49:20.526975 1 trace.go:81] Trace[1080159501]: "Create /api/v1/namespaces/ingress-nginx/pods" (started: 2019-11-19 13:48:50.512338394 +0000 UTC m=+1121687.622499007) (total time: 30.014606337s): Trace[1080159501]: [30.014606337s] [30.000487738s] END W1119 13:49:20.527584 1 dispatcher.go:105] Failed calling webhook, failing open registry-admission.tools.wmflabs.org: failed calling webhook "registry-admission.tools.wmflabs.org": Post https://registry-admission.registry-admission.svc:443/?timeout=30s: context deadline exceeded E1119 13:49:20.527737 1 dispatcher.go:106] failed calling webhook "registry-admission.tools.wmflabs.org": Post https://registry-admission.registry-admission.svc:443/?timeout=30s: context deadline exceeded
This prevents the ingress-nginx pod from being created apparently.