upgrade CRM* machines to buster
those machines are downtime-sensitive enough to warrant a tracking ticket to ensure proper coordination among all teams.
we originally wanted to do this before november, but time is running out, so this is being pushed out to january.
in the meantime, we could consider migrating the machines to the FSN cluster to ensure filesystem-level snapshot to give us rollback capabilities. we should do this in a near-zero downtime migration, that said.