It would be nice if the device lab image was automatically rebuilt when changes to the build recipe are submitted. Right now, I manually build it on my laptop and upload to my home directory on people.wikimedia.org, a process that takes ~45 min.

Alternatively, we could possibly run a nightly build job from cron. (This might require provisioning a build host. It feels like a waste of resources, which is why I'd prefer to get it running via the pool of CI workers instead.)

When building locally, I use fakemachine and QEMU to run the Arm bits. Last week I did some prototyping to verify that this should still work in a container, but it's not clear if Gitlab's other sandboxing might interfere.