[BUG] Review MAINTENACE.md documentation (Kubernetes section)

[plirglo]

Describe the bug Please review MAINTENANCE.md documentation since some of solutions described there does not work

How to reproduce Steps to reproduce the behavior:

1. Installed kubernetes cluster
2. Exampled command: Documented:

root@primary01:~# kubectl get cs --kubeconfig=/etc/kubernetes/admin.conf
NAME                 STATUS    MESSAGE             ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-0               Healthy   {"health":"true"}

Real status (cluster seems to work correctly):

kubectl get cs
NAME                 STATUS      MESSAGE                                                                                     ERROR
controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: connect: connection refused
scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused
etcd-0               Healthy     {"health":"true"}

Expected behavior Test all commands described there and modify documentation, since it looks like cs command stopped working, and has been deprecated in later releases. Find and document alternative commands to provide not experienced user clear path of checking if cluster works properly.

Environment

• Cloud provider: All
• OS: Tested on Ubuntu

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DoD checklist

• Changelog
  • [ ] updated
  • [ ] not needed
• COMPONENTS.md
  • [ ] updated
  • [ ] not needed
• Schema
  • [ ] updated
  • [ ] not needed
• Backport tasks
  • [ ] created
  • [ ] not needed
• Documentation
  • [ ] added
  • [ ] updated
  • [ ] not needed
• [ ] Feature has automated tests
• [ ] Automated tests passed (QA pipelines)
  • [ ] apply
  • [ ] upgrade
  • [ ] backup/restore
• [ ] Idempotency tested
• [ ] All conversations in PR resolved