xgitlab.cels.anl.gov is now deprecated. If you're a project owner and wish to continue to host this project in CELS gitlab, see https://help.cels.anl.gov/docs/migrating-from-legacy-to-gce/gitlab/ for instructions on how to have your project migrated to the new gitlab server.
This server will be retired on December 15, 2022.
This also allocates tags values per-comm, since NBC post order is only required to be consistent on a per-communicator basis. Reviewed by buntinas@.