Readiness as no reasoning to be cluster scope
because that is not how the k8s networking works
for pods, all the pods to a deployment are not
sharing the network in a singleton. Instead they
are run as local scopes to themselves, with
readiness failures the pod is potentially taken
out of the network to be resolvable - this
affects the distributed setup in myriad of
different ways.
Instead readiness should behave like liveness
with local scope alone, and should be a dummy
implementation.
This PR all the startup times and overal k8s
startup time dramatically improves.
Added another handler called as `/minio/health/cluster`
to understand the cluster scope health.
- Add head method for healthcheck endpoint. Some platforms/users
may use the HTTP Head method to check for health status.
- Add liveness and readiness probe examples in Kubernetes yaml
example docs. Note that readiness probe not added to StatefulSet
example due to https://github.com/kubernetes/kubernetes/issues/27114
This PR adds readiness and liveness endpoints to probe Minio server
instance health. Endpoints can only be accessed without authentication
and the paths are /minio/health/live and /minio/health/ready for
liveness and readiness respectively.
The new healthcheck liveness endpoint is used for Docker healthcheck
now.
Fixes#5357Fixes#5514
