Automatically establish ssh tunnel to remote postgresql db server on boot, and auto re-establish if connection is lost (eg reboot of remote machine or network failure). Requires autossh.

autossh-tunnel.conf

# Modified version of technique borrowed from
# http://theantway.com/2012/08/how-to-create-ssh-tunnel-at-boot-time-under-ubuntu/
# Place in /etc/init/
# autossh

description "autossh daemon"

start on net-device-up IFACE=eth1
stop on runlevel [01S6]

respawn
respawn limit 5 60 # respawn max 5 times in 60 seconds

script
    export AUTOSSH_PIDFILE=/var/run/autossh.pid
    export AUTOSSH_POLL=60
    export AUTOSSH_FIRST_POLL=30
    export AUTOSSH_GATETIME=0
    export AUTOSSH_DEBUG=1
    autossh -M 0 -2 -N -L 5432:localhost:5432 USERNAME@REMOTE.int -p REMOTE_PORT -o "ServerAliveInterval 60" -o "ServerAliveCountMax 3" -o BatchMode=yes -o StrictHostKeyChecking=no -i /path/to/.ssh/id_rsa
end script

autossh on systemd
https://gist.github.com/thomasfr/9707568