# user@.service

## 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
    
           /usr/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_ when started, and removes it when it is
           stopped. It also might apply runtime quota settings on /tmp/
           and/or /dev/shm/ for the user.  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@1000.service
               │ │ │ ├─pulseaudio.service
               │ │ │ │ └─2386 /usr/bin/pulseaudio --daemonize=no
               │ │ │ └─gnome-terminal-server.service
               │ │ │   └─init.scope
               │ │ │     ├─ 4127 /usr/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@1001.service
               │     ├─init.scope
               │     │ ├─6680 /usr/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@1000.service). User with UID 1001 is logged in using
           **ssh**(session-20.scope) and also has a user manager instance
           running (user@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
               # /usr/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 do not 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.
    


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