Hi Store Team 
We - the Ubuntu HPC team - recently added support for system usernames within the Slurm snap as some of the daemons bundled in the snap STRONGLY prefer to not be run as root.
Unfortunately, we are confused by the system usernames documentation as it states that the snap_daemon system username is now deprecated as of snapd 2.61 and _daemon_ should be used instead. We updated the Slurm snap to use the _daemon_ name, and it works well in our initial testing within deployed Slurm clusters.
However, things go broke when we attempt to upload a new Slurm snap revision to the Snap Store. The uploads are automatically rejected with the failure being that _daemon_ is an unsupported system username:
unsupported system-username: _daemon_ lint-snap-v2_system-usernames (_daemon_)
So our question is this; do we use snap_daemon or _daemon_? It’s not exactly clear from the documentation which system username we should be using. We’re currently on snapd 2.63, so we don’t want to use snap_daemon as it’s now deprecated. We’re going to revert back to snap_daemon for the time being as need the Slurm snap patches for some PoCs that we’re building out.
Screenshot below for more info of what we’re seeing within the Store interface:
