nixos/systemd/userdbd: add warning for system users >= UID 1000

When a disposition is not set in a user record, systemd determines user
disposition depending on the range the user's UID falls in. For system
users with UIDs above 1000, this will cause them to be incorrectly
identified as "regular" users.

This will cause `userctl` to report the user as a regular user, and more
importantly, `systemd-homed` will not run the first boot user creation
flow, as regular users are already present on the machine (when they are
really system users).

The most common source of high UID system users will undoubtedly be Nix
build users, so the warning provides additional guidance on how to
remove them or adjust their IDs to be within the system range.

The warning is shown only when userdbd/homed is enabled, and the option
to hide the warning is deliberately hidden, to ensure users will have to
read and acknowledge the warning before proceeding, as otherwise users
could end up deploying an OS with no users and no way of creating one
due to the first boot flow being skipped.

0 files changed, 0 insertions, 0 deletions