Kind or Kubernetes inside Docker is a tool for running local Kubernetes clusters using lightweight Docker container “nodes” used for local development, testing, and prototyping.

The blog explains 3 ways to SSH into Docker containers - using the Docker exec, via SSH, and via another Docker container.

Alternate Use cases for a Bastion Host are VPN alternative, authentication gateway, file transfers, share credentials, intrusion detection, software, etc

A Bastion Host is a dedicated computer used to access an infrastructure resource and helps compartmentalize the downstream resources.