Debugging
- https://kubernetes.io/docs/tasks/administer-cluster/dns-debugging-resolution/
- https://dnschecker.org
- https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/
- https://github.com/nicolaka/netshoot
- https://www.redhat.com/sysadmin/using-nfsstat-nfsiostat