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diff --git a/man/user@.service.xml b/man/user@.service.xml new file mode 100644 index 0000000..0cf7f02 --- /dev/null +++ b/man/user@.service.xml @@ -0,0 +1,194 @@ +<?xml version="1.0"?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="user@.service"> + <refentryinfo> + <title>user@.service</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>user@.service</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>user@.service</refname> + <refname>user-runtime-dir@.service</refname> + <refname>systemd-user-runtime-dir</refname> + <refpurpose>System units to start the user manager</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>user@<replaceable>UID</replaceable>.service</filename></para> + <para><filename>user-runtime-dir@<replaceable>UID</replaceable>.service</filename></para> + <para><filename>/usr/lib/systemd/systemd-user-runtime-dir</filename></para> + <para><filename>user-<replaceable>UID</replaceable>.slice</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>The <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> + system manager (PID 1) starts user manager instances as + <filename>user@<replaceable>UID</replaceable>.service</filename>, 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 <command>systemd --user</command> instance manages a + hierarchy of units specific to that user. See + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> for a + discussion of units and + <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for a + list of units that form the basis of the unit hierarchies of system and user units.</para> + + <para><filename>user@<replaceable>UID</replaceable>.service</filename> is accompanied by the + system unit <filename>user-runtime-dir@<replaceable>UID</replaceable>.service</filename>, which + creates the user's runtime directory + <filename>/run/user/<replaceable>UID</replaceable></filename>, and then removes it when this + unit is stopped. <filename>user-runtime-dir@<replaceable>UID</replaceable>.service</filename> + executes the <filename>systemd-user-runtime-dir</filename> binary to do the actual work.</para> + + <para>User processes may be started by the <filename>user@.service</filename> instance, in which + case they will be part of that unit in the system hierarchy. They may also be started elsewhere, + for example by + <citerefentry project='die-net'><refentrytitle>sshd</refentrytitle><manvolnum>8</manvolnum></citerefentry> or a + display manager like <command>gdm</command>, in which case they form a .scope unit (see + <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>). + Both <filename>user@<replaceable>UID</replaceable>.service</filename> and the scope units are + collected under the <filename>user-<replaceable>UID</replaceable>.slice</filename>.</para> + + <para>Individual <filename>user-<replaceable>UID</replaceable>.slice</filename> slices are + collected under <filename>user.slice</filename>, see + <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>. + </para> + </refsect1> + + <refsect1> + <title>Controlling resources for logged-in users</title> + + <para>Options that control resources available to logged-in users can be configured at a few + different levels. As described in the previous section, <filename>user.slice</filename> 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. <filename + index="false">/etc/systemd/system/user.slice.d/resources.conf</filename>. + </para> + + <para>The processes of a single user are collected under + <filename>user-<replaceable>UID</replaceable>.slice</filename>. Resource limits for that user + can be configured through drop-ins for that unit, e.g. <filename + index="false">/etc/systemd/system/user-1000.slice.d/resources.conf</filename>. If the limits + should apply to all users instead, they may be configured through drop-ins for the truncated + unit name, <filename>user-.slice</filename>. For example, configuration in <filename + index="false">/etc/systemd/system/user-.slice.d/resources.conf</filename> is included in all + <filename>user-<replaceable>UID</replaceable>.slice</filename> units, see + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for a discussion of the drop-in mechanism.</para> + + <para>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 + <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + This PAM module communicates with + <citerefentry><refentrytitle>systemd-logind</refentrytitle><manvolnum>8</manvolnum></citerefentry> + 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 + <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + 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.</para> + + <para>In general any resources that apply to units may be set for + <filename>user@<replaceable>UID</replaceable>.service</filename> and the slice + units discussed above, see + <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for an overview.</para> + </refsect1> + + <refsect1> + <title>Examples</title> + <example> + <title>Hierarchy of control groups with two logged in users</title> + + <programlisting>$ 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 +…</programlisting> + <para>User with UID 1000 is logged in using <command>gdm</command> (<filename + index="false">session-4.scope</filename>) and + <citerefentry project='die-net'><refentrytitle>ssh</refentrytitle><manvolnum>1</manvolnum></citerefentry> + (<filename index="false">session-19.scope</filename>), and also has a user manager instance + running (<filename index="false">user@1000.service</filename>). User with UID 1001 is logged + in using <command>ssh</command> (<filename index="false">session-20.scope</filename>) and + also has a user manager instance running (<filename + index="false">user@1001.service</filename>). Those are all (leaf) system units, and form + part of the slice hierarchy, with <filename index="false">user-1000.slice</filename> and + <filename index="false">user-1001.slice</filename> below <filename + index="false">user.slice</filename>. User units are visible below the + <filename>user@.service</filename> instances (<filename + index="false">pulseaudio.service</filename>, <filename + index="false">gnome-terminal-server.service</filename>, <filename + index="false">init.scope</filename>, <filename index="false">sleep.service</filename>). + </para> + </example> + + <example> + <title>Default user resource limits</title> + + <programlisting>$ 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%</programlisting> + <para>The <filename>user-<replaceable>UID</replaceable>.slice</filename> 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.</para> + </example> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry> + </para> + </refsect1> +</refentry> |