This GitHub Action opens an SSH connection to the github actions runner through an intermediary server. It is intended to debug jobs through SSH.

The gateway server has to be accessible from internet. The gateway ssh server configuration (usually in /etc/ssh/sshd_config) needs the following configuration

AllowTcpForwarding yes
GatewayPorts yes

First add the action to your workflow.

  - name: Debug through SSH
    uses: edipizarro/runner-open-ssh @main
    with:
      sshPublicKey: ${{ secrets.SSH_PUBLIC_KEY }}
      gatewayPrivateKey: ${{ secrets.GATEWAY_PRIVATE_KEY }}
      gatewayIP: ${{ secrets.GATEWAY_IP }}
      maxLifeTime: 30

• sshPublicKey: Public SSH key that will be authorized in the github runner.
• gatewayPrivateKey: Private SSH Key that can access the Gateway server. The action will use this key to SSH to the gateway server and open a proxy on port 2222, consequently, the gateway server will be able to SSH with the runner.
• gatewayIP is the public IP of the gateway (used by the runner to ssh to the gateway)
• maxLifeTime is the maximum life of the connection in seconds. default value is 3600 (1 hour). When the action SSH's to the gateway, it runs "sleep ${maxLifeTime}".

After the job is run, the runner creates a proxy on the gateway on port 2222. So, to connect to the runner, first ssh to the gateway server, and from there run "ssh -p 2222 runner@localhost".

The ssh proxy connection is run as a background process (using the ampersand &). And to keep the action alive a tmux terminal is attached.

If you want to close the connection before the maxLifeTime (to continue to the next action or just to finish the job), execute 'tmux kill-session'. This will kill the tmux session and then the action will finish. You can also just cancel the action.