TiDB Pod Probe doesn't work with TLS

[weekface]

TiDB Pod now has a Probe to probe TiDB Server's /status path. K8s Probe cannot send client certificate when requested. Now that TiDB Server has enabled TLS, TiDB Server has forced to verify the client certificate, so the Probe always failed to work.

Readiness probe failed: Get https://10.244.0.17:10080/status: remote error: tls: bad certificate

[tennix]

Can we use a command to do the health check? We can use local tls certificate to request port 10080.

https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/#define-a-liveness-command

[tennix]

However, tidb docker image does not contain curl and the builtin wget does not support specifying TLS certificates. So in order to use command to do health check, we may need to install curl in the tidb docker image.