How to start systemd user services at boot

Covers: ubuntu 22.04

If you separate systemd services with different accounts, you may encounter the problem, that a service is not restarted at boot time, but once you login into the account. The user (not system-wide) services are ran that way.

To change the behavior (i.e. run the user services at boot time, regardless login), you should not put it in home folder, but in /etc/systemd/system/,

Otherwise, you can keep the services in $HOME and fake users logging in via:

sudo loginctl enable-linger <your_user_name>

enable-linger [USER…], disable-linger [USER…] Enable/disable user lingering for one or more users. If enabled for a specific user, a user manager is spawned for the user at boot and kept around after logouts. This allows users who are not logged in to run long-running services.

Note:

loginctl enable-linger <user> does permanently enable it even across reboots. You can verify with ls /var/lib/systemd/linger/ which lists all users where linger is enabled (a filename in an username). One of the tasks for loginctl is to create/remove the file.

Note (see ref 2):

To make the service run on boot, you should not put it in your home folder. Instead, put it under /etc/systemd/system/. This is the folder meant to be used by the system administrator (i.e. you) to add new system-wide services.

Other folders include:

/usr/lib/systemd/system/ is meant for packages that want to install unit files, though under Debian and Ubuntu the folder is actually /lib/systemd/system/ because the various bin and lib folders have not been merged into a unified /usr/ prefix yet.
/usr/local/lib/systemd/system/ is for installing units by locally compiled packages.

Refs: