systemd --user
runs as a system service called [email protected]
. This is a template service. Your instance might be [email protected]
. The number is your user ID (id -u
).
The system shutdown procedure will signal [email protected]
to stop, with the usual signal SIGTERM
. In response, the systemd --user
process will signal each user service to stop.[*]
systemctl cat [email protected]
suggests there is little point setting a user service timeout (grace period) any longer than 120 seconds. After that, all the user services will recieve SIGKILL
from the main system (PID 1). SIGKILL
is immediately fatal.
To understand the settings in this file, see man systemd.kill
, and also man systemd.service
.
[*] Technically, what systemd --user
does in response to SIGTERM
is to activate the user unit exit.target
. This is mentioned in man systemd
. For more information about exit.target
: systemctl cat exit.target
will tell you to look in man systemd.special
:-).