Comment by chuckadams

The irony is that Kubernetes already provides a "ssh into any container" ability, and it's provided directly by k8s, no sshd needed (it's not the ssh protocol but it's good enough to get a shell). Not sure it's advisable to do with any user but an admin, but the standard workflow with k8s is not to shell into running containers anyway, it's to rebuild the container and redeploy the pod.