Docker SSH Tunnel

This Docker creates a simple SSH tunnel over a server. It is very useful when your container needs to access to an external protected resource. In this case this container might behave like a proxy to outer space inside your Docker network.

Usage

1. First you should create a config file in your local directory. For simplicity you can create this file in ~/.ssh in your local machine.

2. Inside ~/.ssh/config put these lines:

    Host mysql-tunnel # You can use any name
            HostName ssh-tunnel.corporate.tld # Tunnel
            IdentityFile ~/.ssh/id_rsa # Private key location
            User cagatay.guertuerk # Username to connect to SSH service
            ForwardAgent yes
            TCPKeepAlive yes
            ConnectTimeout 5
            ServerAliveCountMax 10
            ServerAliveInterval 15

3. Don't forget to put your private key (id_rsa) to ~/.ssh folder.

4. Now in docker-compose.yml you can define the tunnel as follows:

    version: '2'
    services:
      mysql:
        image: cagataygurturk/docker-ssh-tunnel:0.0.1
        volumes:
          - $HOME/.ssh:/root/ssh:ro
        environment:
          TUNNEL_HOST: mysql-tunnel
          REMOTE_HOST: tunneled-sql.corporate.internal.tld
          LOCAL_PORT: 3306
          REMOTE_PORT: 3306

5. Run docker-compose up -d

After you start up docker containers, any container in the same network will be able to access to tunneled mysql instance using tcp://mysql:3306. Of course you can also expose port 3306 to be able to access to tunneled resource from your host machine.