This allows users who are not logged in to run long-running
services. Takes one or more user names or numeric UIDs as
argument. If no argument is specified, enables/disables
- lingering for the user of the session of the caller.
+ lingering for the user of the session of the caller.</para>
+
+ <para>See also <varname>KillUserProcesses=</varname> setting in
+ <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para></listitem>
</varlistentry>
otherwise.</para>
</refsect1>
+ <refsect1>
+ <title>Examples</title>
+
+ <example>
+ <title>Querying user status</title>
+
+ <programlisting>$ loginctl user-status
+fatima (1005)
+ Since: Sat 2016-04-09 14:23:31 EDT; 54min ago
+ State: active
+ Sessions: 5 *3
+ Unit: user-1005.slice
+ ├─user@1005.service
+ ...
+ ├─session-3.scope
+ ...
+ └─session-5.scope
+ ├─3473 login -- fatima
+ └─3515 -zsh
+
+Apr 09 14:40:30 laptop login[2325]: pam_unix(login:session):
+ session opened for user fatima by LOGIN(uid=0)
+Apr 09 14:40:30 laptop login[2325]: LOGIN ON tty3 BY fatima
+</programlisting>
+
+ <para>There are two sessions, 3 and 5. Session 3 is a graphical session,
+ marked with a star. The tree of processing including the two corresponding
+ scope units and the user manager unit are shown.</para>
+ </example>
+ </refsect1>
+
<xi:include href="less-variables.xml" />
<refsect1>
<varlistentry>
<term><varname>KillUserProcesses=</varname></term>
- <listitem><para>Takes a boolean argument. Configures whether
- the processes of a user should be killed when the user
- completely logs out (i.e. after the user's last session
- ended). Defaults to <literal>no</literal>.</para>
-
- <para>Note that setting <varname>KillUserProcesses=1</varname>
+ <listitem><para>Takes a boolean argument. Configures whether the processes of a
+ user should be killed when the user logs out. If true, the scope unit
+ corresponding to the session and all processes inside that scope will be
+ terminated. If false, the scope is "abandonded", see
+ <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ and processes are not killed. Defaults to <literal>no</literal>.</para>
+
+ <para>In addition to session processes, user process may run under the user
+ manager unit <filename>user@.service</filename>. Depending on the linger
+ settings, this may allow users to run processes independent of their login
+ sessions. See the description of <command>enable-linger</command> in
+ <citerefentry><refentrytitle>loginctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+ </para>
+
+ <para>Note that setting <varname>KillUserProcesses=yes</varname>
will break tools like
- <citerefentry project='die-net'><refentrytitle>screen</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para></listitem>
+ <citerefentry project='die-net'><refentrytitle>screen</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ and
+ <citerefentry project='die-net'><refentrytitle>tmux</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ unless they are moved out of the session scope. See example in
+ <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
+ </para></listitem>
</varlistentry>
<varlistentry>
<term><varname>KillOnlyUsers=</varname></term>
<term><varname>KillExcludeUsers=</varname></term>
- <listitem><para>These settings take space-separated lists of
- usernames that influence the effect of
- <varname>KillUserProcesses=</varname>. If not empty, only
- processes of users listed in <varname>KillOnlyUsers=</varname>
- will be killed when they log out entirely. Processes of users
- listed in <varname>KillExcludeUsers=</varname> are excluded
- from being killed. <varname>KillExcludeUsers=</varname>
- defaults to <literal>root</literal> and takes precedence over
- <varname>KillOnlyUsers=</varname>, which defaults to the empty
- list.</para></listitem>
+ <listitem><para>These settings take space-separated lists of usernames that
+ determine to which users the <varname>KillUserProcesses=</varname> setting
+ applies. A user name may be added to <varname>KillExcludeUsers=</varname> to
+ exclude the processes in the session scopes of that user from being killed even if
+ <varname>KillUserProcesses=yes</varname> is set. If
+ <varname>KillExcludeUsers=</varname> is not set, the <literal>root</literal> user
+ is excluded by default. <varname>KillExcludeUsers=</varname> may be set to an
+ empty value to override this default. If a user is not excluded,
+ <varname>KillOnlyUsers=</varname> is checked next. A list of user names may be
+ specified in <varname>KillOnlyUsers=</varname>, to only include those
+ users. Otherwise, all users are included.</para></listitem>
</varlistentry>
<varlistentry>
<programlisting># systemd-run -t --send-sighup /bin/bash</programlisting>
</example>
+
+ <example>
+ <title>Start <command>screen</command> as a user service</title>
+
+ <programlisting>$ systemd-run --scope --user screen
+Running scope as unit run-r14b0047ab6df45bfb45e7786cc839e76.scope.
+
+$ screen -ls
+There is a screen on:
+ 492..laptop (Detached)
+1 Socket in /var/run/screen/S-fatima.
+</programlisting>
+
+ <para>This starts the <command>screen</command> process as a child of the
+ <command>systemd --user</command> process that was started by
+ <filename>user@.service</filename>, in a scope unit. A
+ <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ unit is used instead of a
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ unit, because <command>screen</command> will exit when detaching from the terminal,
+ and a service unit would be terminated. Running <command>screen</command>
+ as a user unit has the advantage that it is not part of the session scope.
+ If <varname>KillUserProcesses=yes</varname> is configured in
+ <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ the default, the session scope will be terminated when the user logs
+ out of that session.</para>
+
+ <para>The <filename>user@.service</filename> is started automatically
+ when the user first logs in, and stays around as long as at least one
+ login session is open. After the user logs out of the last session,
+ <filename>user@.service</filename> and all services underneath it
+ are terminated. This behaviour is the default, when "lingering" is
+ not enabled for that user. Enabling lingering means that
+ <filename>user@.service</filename> is started automatically during
+ boot, even if the user is not logged in, and that the service is
+ not terminated when the user logs out.</para>
+
+ <para>Enabling lingering allows the user to run processes without being logged in,
+ for example to allow <command>screen</command> to persist after the user logs out,
+ even if the session scope is terminated. In the default configuration, users can
+ enable lingering for themselves:</para>
+
+ <programlisting>$ loginctl enable-linger</programlisting>
+ </example>
</refsect1>
<refsect1>
projects / thirdparty / systemd.git / commitdiff
