systemd-user-sessions.service, systemd-user-sessions — Permit user logins after boot, prohibit user logins at shutdown
systemd-user-sessions.service
/usr/lib/systemd/systemd-user-sessions
systemd-user-sessions.service is a
service that controls user logins through
pam_nologin(8).
After basic system initialization is complete, it removes
/run/nologin, thus permitting logins. Before
system shutdown, it creates /run/nologin, thus
prohibiting further logins.