Cluster health checks

https://kubernetes.io/docs/tasks/debug-application-cluster/debug-cluster/

kubectl cluster-info
kubectl get nodes

API checks

https://kubernetes.io/docs/reference/using-api/health-checks/

curl -k https://localhost:6443/healthz
..

or

kubectl get --raw='/healthz?verbose'
kubectl get --raw='/readyz?verbose'
kubectl get --raw='/livez?verbose'