Is it possible to health check a Kubernetes API server over HTTP or TCP?

kubernetes load-balancing digital-ocean kubernetes-health-check

do a kubectl proxy and then use postman or any tool to send a get request to http://127.0.0.1:8001/healthz/poststarthook/apiservice-status-available-controller

you can use other too

/healthz,
/healthz/autoregister-completion,
/healthz/ping,
/healthz/poststarthook/apiservice-registration-controller,
/healthz/poststarthook/apiservice-status-available-controller,
/healthz/poststarthook/bootstrap-controller,
/healthz/poststarthook/ca-registration,
/healthz/poststarthook/extensions/third-party-resources,
/healthz/poststarthook/generic-apiserver-start-informers,
/healthz/poststarthook/kube-apiserver-autoregistration,
/healthz/poststarthook/start-apiextensions-controllers,
/healthz/poststarthook/start-apiextensions-informers,
/healthz/poststarthook/start-kube-aggregator-informers,
/healthz/poststarthook/start-kube-apiserver-informers,

kubernetes load-balancing digital-ocean kubernetes-health-check

You can hit API server nodes on port 8080 at /healthz and expect to get back a 200 with a body of ok if the API server is up and in good health.

See some test code that hits this endpoint for more details: https://github.com/kubernetes/kubernetes/blob/fe3e7482764ace362b465405c45780d03a8c6706/staging/src/k8s.io/apiserver/pkg/server/healthz/healthz_test.go#L28