Telling Cockpit to listen on a specific IP address

[yrro]

To solve a conflict between cockpit and prometheus, which both want to use port 9090/tcp, I added an additional IP address to my machine, and told prometheus to listen on 192.0.2.10:9090. However, this still conflicts with cockpit.socket which is unable to bind to 0.0.0.0:9090 if prometheus starts first.

I modified cockpit.socket to make it bind to the machine's original IP address:

[Socket]
FreeBind=true
ListenStream=
ListenStream=192.0.2.5:9090

I added FreeBind= so that cockpit.socket can start before the IP address is available. Originally I tried adding Wants=network-online.target but this caused an ordering cycle (network-online.target -> NetworkManager-wait-online.service -> basic.target -> sockets.target -> cockpit.socket -> network-online.target).

I hope someone else finds this useful.

[yrro]

Hah, I see the info about FreeBind= is already in the guide! I searched the discussions, but didn't see it in the manual... 🤦

[martinpitt]

Thanks @yrro ! Just for other readers, another way is to change cockpit's port to something else. https://cockpit-project.org/guide/latest/listen describes that as well.