I am trying to create a configuration for the purpose of limiting CPU/MEM/etc. per-user.
According to systemd-cgls, it would be best to specify the limit at user-N.slice (e.g. user-1000.slice), which is under global user.slice. The user-1000.slice has typically [email protected] an and session-cN.scope under itself.

Since I want to limit together both the lingering services (in [email protected]) and interactive login, I tried to create a config following the well-known [email protected]-style templating scheme: /etc/systemd/system/user-.slice.d/foo.conf. That doesn't get loaded. It would be a nice feature to have "-" (hyphen) be a templating pattern. This would allow the operator to configure all user slices at once.