SSH Debug

SSH debugging allows a user to identify and resolve issues or errors that occur through the secure shell (SSH) connection between a client and a server.

To enhance the security of the runner and the infrastructure behind the runner, only user ssh-keys registered on Authorized Keys are allowed by default on tmate-ssh-server charm.

Authorized keys are registered via action-tmate’s limit-access-to-actor feature. This feature uses GitHub users’s SSH key to launch an instance of tmate session with -a option, which adds the user’s SSH key to ~/.ssh/authorized_keys.

Firewall rules

By default, if there are any overlapping IPs within the denylist config option with the IP assigned to tmate-ssh-server, an exception to that IP will be made so that the debug-ssh relation can be set up correctly.