/etc/adduser.conf should default to use extra_users

[Ben Howard]

On Snappy, since creation of traditional users is a no-op, /etc/adduser.conf should default to using
# use extrausers by default
USE_EXTRAUSERS=1

This change would make it so that "adduser" works without having to add "--extrauser". And it means that cloud-init would be able to create users.

[Ben Howard (darkmuggle-deactivatedaccount)]

This request is important for Cloud Builds, especially for Azure.

[Zygmunt Krynicki (zyga)]

Looking at the core snap currently it doesn't set USE_EXTRAUSERS=1 (that line is near the bottom of the configuration file and is commented out). I wonder if this is still an issue, perhaps some other layer was adjusted to make this the default (since the core snap has a few custom packages).

[Oliver Grawert (ogra)]

there was no adjustment apart from hardcoding --extrausers everywhere in the image when any of the password-db related commands are used ... it would still be useful to instead switch the default and be able to drop that hardcoding in a bunch of places instead.