man > user@.service(5)

USER@.SERVICE(5)                            user@.service                           USER@.SERVICE(5)



NAME
       user@.service, user-runtime-dir@.service, systemd-user-runtime-dir - System units to start
       the user manager

SYNOPSIS
       user@UID.service

       user-runtime-dir@UID.service

       /lib/systemd/systemd-user-runtime-dir

       user-UID.slice

DESCRIPTION
       The systemd(1) system manager (PID 1) starts user manager instances as user@UID.service, with
       the user's numerical UID used as the instance identifier. These instances use the same
       executable as the system manager, but running in a mode where it starts a different set of
       units. Each systemd --user instance manages a hierarchy of units specific to that user. See
       systemd(1) for a discussion of units and systemd.special(7) for a list of units that form the
       basis of the unit hierarchies of system and user units.

       user@UID.service is accompanied by the system unit user-runtime-dir@UID.service, which
       creates the user's runtime directory /run/user/UID, and then removes it when this unit is
       stopped.  user-runtime-dir@UID.service executes the systemd-user-runtime-dir binary to do the
       actual work.

       User processes may be started by the user@.service instance, in which case they will be part
       of that unit in the system hierarchy. They may also be started elsewhere, for example by
       sshd(8) or a display manager like gdm, in which case they form a .scope unit (see
       systemd.scope(5)). Both user@UID.service and the scope units are collected under the
       user-UID.slice.

       Individual user-UID.slice slices are collected under user.slice, see systemd.special(7).

CONTROLLING RESOURCES FOR LOGGED-IN USERS
       Options that control resources available to logged-in users can be configured at a few
       different levels. As described in the previous section, user.slice contains processes of all
       users, so any resource limits on that slice apply to all users together. The usual way to
       configure them would be through drop-ins, e.g.
       /etc/systemd/system/user.slice.d/resources.conf.

       The processes of a single user are collected under user-UID.slice. Resource limits for that
       user can be configured through drop-ins for that unit, e.g.
       /etc/systemd/system/user-1000.slice.d/resources.conf. If the limits should apply to all users
       instead, they may be configured through drop-ins for the truncated unit name, user-.slice.
       For example, configuration in /etc/systemd/system/user-.slice.d/resources.conf is included in
       all user-UID.slice units, see systemd.unit(5) for a discussion of the drop-in mechanism.

       When a user logs in and a .scope unit is created for the session (see previous section), the
       creation of the scope may be managed through pam_systemd(8). This PAM module communicates
       with systemd-logind(8) to create the session scope and provide access to hardware resources.
       Resource limits for the scope may be configured through the PAM module configuration, see
       pam_systemd(8). Configuring them through the normal unit configuration is also possible, but
       since the name of the slice unit is generally unpredictable, this is less useful.

       In general any resources that apply to units may be set for user@UID.service and the slice
       units discussed above, see systemd.resource-control(5) for an overview.

EXAMPLES
       Example 1. Hierarchy of control groups with two logged in users

           $ systemd-cgls
           Control group /:
           -.slice
           ├─user.slice
           │ ├─user-1000.slice
           │ │ ├─user AT 1000.service
           │ │ │ ├─pulseaudio.service
           │ │ │ │ └─2386 /usr/bin/pulseaudio --daemonize=no
           │ │ │ └─gnome-terminal-server.service
           │ │ │   └─init.scope
           │ │ │     ├─ 4127 /libexec/gnome-terminal-server
           │ │ │     └─ 4198 zsh
           │ │ ...
           │ │ └─session-4.scope
           │ │   ├─ 1264 gdm-session-worker [pam/gdm-password]
           │ │   ├─ 2339 /usr/bin/gnome-shell
           │ │   ...
           │ │ ├─session-19.scope
           │ │   ├─6497 sshd: zbyszek [priv]
           │ │   ├─6502 sshd: zbyszek@pts/6
           │ │   ├─6509 -zsh
           │ │   └─6602 systemd-cgls --no-pager
           │ ...
           │ └─user-1001.slice
           │   ├─session-20.scope
           │   │ ├─6675 sshd: guest [priv]
           │   │ ├─6708 sshd: guest@pts/6
           │   │ └─6717 -bash
           │   └─user AT 1001.service
           │     ├─init.scope
           │     │ ├─6680 /lib/systemd/systemd --user
           │     │ └─6688 (sd-pam)
           │     └─sleep.service
           │       └─6706 /usr/bin/sleep 30
           ...

       User with UID 1000 is logged in using gdm (session-4.scope) and ssh(1) (session-19.scope),
       and also has a user manager instance running (user AT 1000.service). User with UID 1001 is
       logged in using ssh (session-20.scope) and also has a user manager instance running
       (user AT 1001.service). Those are all (leaf) system units, and form part of the slice hierarchy,
       with user-1000.slice and user-1001.slice below user.slice. User units are visible below the
       user@.service instances (pulseaudio.service, gnome-terminal-server.service, init.scope,
       sleep.service).

       Example 2. Default user resource limits

           $ systemctl cat user-1000.slice
           # /lib/systemd/system/user-.slice.d/10-defaults.conf
           # ...
           [Unit]
           Description=User Slice of UID %j
           After=systemd-user-sessions.service

           [Slice]
           TasksMax=33%

       The user-UID.slice units by default don't have a unit file. The resource limits are set
       through a drop-in, which can be easily replaced or extended following standard drop-in
       mechanisms discussed in the first section.

SEE ALSO
       systemd(1), systemd.service(5), systemd.slice(5), systemd.resource-control(5),
       systemd.exec(5), systemd.special(7), pam(8)



systemd 249                                                                         USER@.SERVICE(5)