Buildbot runbook

Our buildbot instance has a habit of breaking due to excess load.

Restarting the worker

If the worker (primary, handling nix evaluations) explodes, it can be restarted.

ssh root@buildbot.lix.systems 'systemctl restart buildbot-worker.service'

Re-trying spurious CI failures

Those with the relevant permissions can click the "rebuild" button on a given CI job, but in order to count for Gerrit's checks and set the Verified +1 flag, you must restart the top-level lix/nix-eval job; restarting e.g. a single test or build will not affect things on the Gerrit side.