Start autossh on system startup

Question

Is there any way to start autossh on startup, so that it starts and sets up the ssh tunnel before a user has even logged in? I boot Ubuntu to terminal, and I'd like that the autossh process starts automatically on startup so I can ssh in.

I've tried adding the command to /etc/rc.local, as well as to create a /etc/init/*.conf script. None of these seems to work.

Answer 1

Using systemd this can be done (sample autossh created for mysql access):

1. Create a systemd file using nano or vim or appropriate editor of choice:

   sudo vim /etc/systemd/system/autossh-mysql-tunnel.service 
   

2. Add the following contents:

   [Unit]
   Description=AutoSSH tunnel service everythingcli MySQL on local port 5000
   After=network.target
   
   [Service]
   Environment="AUTOSSH_GATETIME=0"
   ExecStart=/usr/bin/autossh -M 0 -o "ServerAliveInterval 30" -o "ServerAliveCountMax 3" -NL 5000:localhost:3306 cytopia@everythingcli.org -p 1022
   
   [Install]
   WantedBy=multi-user.target
   

3. Reload systemd:

   sudo systemctl daemon-reload
   

4. Start the Autossh service:

   sudo systemctl start autossh-mysql-tunnel.service
   

5. Enable at boot:

   sudo systemctl enable autossh-mysql-tunnel.service
   

6. Check status with:

   sudo systemctl status autossh-mysql-tunnel
   

Note

There is however an important thing to note about systemd and AutoSSH: -f (background usage) already implies AUTOSSH_GATETIME=0, however -f is not supported by systemd.

So in the case of systemd you need to make use of AUTOSSH_GATETIME

Source

• https://www.everythingcli.org/ssh-tunnelling-for-fun-and-profit-autossh/
• https://www.freedesktop.org/software/systemd/man/systemd.service.html

Answer 2

I added a -N to the command to get this to work. -N tells autossh to connect and do nothing. Without it my ssh session was logging in then immediately exiting. I also set it up to use a local user along with a .ssh/config file (/home/myuser/.ssh/config) which contains my tunnel rules.

# cat /etc/systemd/system/autossh.service
[Unit]
Description=AutoSSH service
After=network.target

[Service]
Environment="AUTOSSH_GATETIME=0"
User=myuser
Group=myuser
ExecStart=/usr/bin/autossh -N -M 0 -o "ServerAliveInterval 30" -o "ServerAliveCountMax 3" -i /home/myuser/.ssh/id_ecdsa_np remoteid@remote
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target