Cockpit runs on the popular port 9090. Chances are that you are going to have a port conflict if you have a couple of other services running. This will lead to Cockpit failing to start.

If you suspect this is the case you can verify it by running:

sudo systemctl status cockpit.socket

or by tailing the syslog:

tail /var/log/syslog

If you do see any errors about Cockpit not starting due to a port conflict, it’s quite easy to rectify. These instructions are for Ubuntu Server Jammy (22.04.2).

  1. Create or edit the /etc/systemd/system/cockpit.socket.d/listen.conf file
  2. Change the ListenStream option to match your required port

The default option will be similar to:

[Socket]
ListenStream=
ListenStream=443

Change it to match your required port:

[Socket]
ListenStream=
ListenStream=<YOUR_NEW_PORT>

Note: the empty ListenStream= directive is needed to reset the previous value of this field. You can find more information about this on the Cockpit documentation

  1. Finally, restart the services to make the change take effect:
sudo systemctl daemon-reload
sudo systemctl restart cockpit.socket