Thanks for you work, I have a few comments though:
1. env DEBIAN_FRONTEND=noninteractive is useless because the job doesn't install any package, but it doesn't hurt.
2. There is no error handling around usermod call. Since this job will run on every boot it is possible that the user is already a member of this group and the job will fail. You should at least test for group membership.
3. The function "exit_job" doesn't exit, you can just remove that line
Thanks for you work, I have a few comments though: FRONTEND= noninteractive is useless because the job doesn't install any package, but it doesn't hurt.
1. env DEBIAN_
2. There is no error handling around usermod call. Since this job will run on every boot it is possible that the user is already a member of this group and the job will fail. You should at least test for group membership.
3. The function "exit_job" doesn't exit, you can just remove that line