This is only valid for on-premise installations. Learn more about on-premise installations here: Installation Documentation
The SSH private key needs to be mapped into the docker container; here is an example configuration where we map from the docker host machine (Linux in this case) to the docker container.
Note: if the key is not connecting to a known host the known hosts file may also need to be mapped (/.ssh/known_hosts).
Here is an example connection we have setup to connect over SSH. We do not provide a username and password as that is instantiated from the SSH key.