This document is best read printed out on paper.
I recently added another apache server to an existing infrastructure, and
I wanted it to be accessible under a similar IP as another server. Due
to the complexity of the website, it was not possible to simply do a reverse
proxy without knowing the correct settings (e.g. X-Forwarded for). Instead,
AutoSSH was used. In the end, I accessed a new port on the existing IP.
Ok, I’m going to get right to the configs that I used. You want the tool, you
don’t need to know all the details.
Here is the crontab script I used. I put this in /etc/crontab, so it has root
after the times. I only use /etc/crontab, as it’s easier to manage.
* * * * * root pgrep autossh > /dev/null || \
A few notes about this. Pgrep will search for autossh. If it doesn’t find it,
then it will try the next command. (—— is an OR). Put the bash script
wherever you want.
This script is obviously what the crontab calls.
logger ” /usr/local/bin/autosshzm script started.”
#source $HOME/.bash_profile #not needed.
logger ” /usr/local/bin/autosshzm sourced.”
-L 0.0.0.0:2:localhost:80 -f user@ipaddress sleep 31536000
1#autossh -M 0 -o “ServerAliveInterval 30” -o “ServerAliveCountMax 3”
-L 0.0.0.0:2:localhost:80 user@ipaddress &>
logger “auto ssh ran”
Note that the second autossh does not work, as it’s missing the sleep and
the -f command. 1 In order for this to work, you’ll also need the following
apt-get install keychain autossh
There were some more setup steps required for keychain… From stackex-
solves this in a painless way. It’s in the repos for Debian/Ubuntu:
sudo apt-get install keychain
and perhaps for many other distros (it looks like it originated
This program will start an ssh-agent if none is running, and
provide shell scripts that can be sourced and connect the current
shell to this particular ssh-agent.
For bash, with a private key named id_rsa, add the following to
keychain –nogui id_rsa
This will start an ssh-agent and add the id_rsa key on the first
login after reboot. If the key is passphrase-protected, it will
also ask for the passphrase. No need to use unprotected keys
anymore! For subsequent logins, it will recognize the agent
and not ask for a passphrase again.
Also, add the following as a last line of your .bashrc:
Figuring this kind of stuff out can take about an hour.
This will let the shell know where to reach the SSH agent managed
by keychain. Make sure that .bashrc is sourced from .profile.
However, it seems that cron jobs still don’t see this. As a
remedy, include the line above in the crontab, just before
your actual command:
* * * * * . ~/.keychain/$HOSTNAME-sh; your-actual-command
The only thing that I needed to do here was
keychain –nogui id rsa
The rest of it (notes about crontab) was not required.
What Did NOT Work
Here’s some things I tried that did not work.
- https://github.com/obfusk/autossh-init – This init script, didn’t do
much for me. Remember, I’m stuck with systemd in Ubuntu 19.04… 2
- Reverse proxy with Apache – As I said, my website 3 was too complex,
and I didn’t want to go down that rabbit hole.
- Starting AutoSSH in rc.local. Didn’t work.
The scourge of deleting software history. Keep backwards compatibility at ALL COSTS, developers.
Some people might call it a web application. I will not.