Start autossh on system startup

16.04 ssh startup autossh

19,033

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

Create a systemd file using nano or vim or appropriate editor of choice:
```
sudo vim /etc/systemd/system/autossh-mysql-tunnel.service 
```

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 [email protected] -p 1022

[Install]
WantedBy=multi-user.target

Reload systemd:
```
sudo systemctl daemon-reload
```

Start the Autossh service:

sudo systemctl start autossh-mysql-tunnel.service

Enable at boot:

sudo systemctl enable autossh-mysql-tunnel.service

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

19,033

ptf

Updated on September 18, 2022

Comments

ptf over 1 year

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.
ptf over 6 years

Thanks! I'm trying this, but when I run sudo service reverse-ssh-tunnel.service status, I get Loaded: not-found (Reason: No such file or directory). Researching this now :)
George Udosen over 6 years

please do sudo systemctl status reverse-ssh-tunnel not sudo service reverse-ssh-tunnel.service status
ptf over 6 years

Can I specify the SSL private key needed to authenticate with the other machine?
George Udosen over 6 years

I believe you mean autossh -i /home/<user>/.ssh/id_rsa -R 22222:localhost:22 <user>@<remote_host>
ptf over 6 years

I needed to add -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no as well. Maybe I just need one of them, haven't tested them individually. Found this here: stackoverflow.com/a/24689061/1211119. However, when I'm looking at the tty1 login screen (I boot to the terminal), the service hasn't yet created the tunnel. If I log in, the service starts.
Gabriel over 6 years

Great answer. @ptf, thanks for commenting with the additional flags. Without those I was getting a 255 return value from ssh. Did you resolve the issue that the tunnel only initiates when you log in?
ptf over 6 years

@Gabriel Hmm, I don't think so. I think I haven't look to much more at it.
friederbluemle over 5 years

Sometimes you want to run under a different user context. To do this: Add User=username to the [Service] section in the systemd file.
fullmooninu about 5 years

Why the "-M 0" is needed?
Al Kasih almost 5 years

This is the only one which is working for my raspberry pi project among all samples I read. However, after 2 days no activity, the connection is closed. When I view it with teamviewer the pi device is still online actually. Can you figure out why and what need to be fiixed here?
haelix almost 3 years

@ptf don't add both -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no, add only -o StrictHostKeyChecking=accept-new. Not redundant and more secure.