man/systemd.slice.xml

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   8   Copyright 2013 Zbigniew Jędrzejewski-Szmek
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  23
  24 <refentry id="systemd.slice">
  25   <refentryinfo>
  26     <title>systemd.slice</title>
  27     <productname>systemd</productname>
  28
  29     <authorgroup>
  30       <author>
  31         <contrib>Developer</contrib>
  32         <firstname>Lennart</firstname>
  33         <surname>Poettering</surname>
  34         <email>lennart@poettering.net</email>
  35       </author>
  36     </authorgroup>
  37   </refentryinfo>
  38
  39   <refmeta>
  40     <refentrytitle>systemd.slice</refentrytitle>
  41     <manvolnum>5</manvolnum>
  42   </refmeta>
  43
  44   <refnamediv>
  45     <refname>systemd.slice</refname>
  46     <refpurpose>Slice unit configuration</refpurpose>
  47   </refnamediv>
  48
  49   <refsynopsisdiv>
  50     <para><filename><replaceable>slice</replaceable>.slice</filename></para>
  51   </refsynopsisdiv>
  52
  53   <refsect1>
  54     <title>Description</title>
  55
  56     <para>A unit configuration file whose name ends in
  57     <literal>.slice</literal> encodes information about a slice which
  58     is a concept for hierarchically managing resources of a group of
  59     processes. This management is performed by creating a node in the
  60     Linux Control Group (cgroup) tree. Units that manage processes
  61     (primarily scope and service units) may be assigned to a specific
  62     slice. For each slice, certain resource limits may be set that
  63     apply to all processes of all units contained in that
  64     slice. Slices are organized hierarchically in a tree. The name of
  65     the slice encodes the location in the tree. The name consists of a
  66     dash-separated series of names, which describes the path to the
  67     slice from the root slice. The root slice is named,
  68     <filename>-.slice</filename>. Example:
  69     <filename>foo-bar.slice</filename> is a slice that is located
  70     within <filename>foo.slice</filename>, which in turn is located in
  71     the root slice <filename>-.slice</filename>.
  72     </para>
  73
  74     <para>Note that slice units cannot be templated, nor is possible to add multiple names to a slice unit by creating
  75     additional symlinks to it.</para>
  76
  77     <para>By default, service and scope units are placed in
  78     <filename>system.slice</filename>, virtual machines and containers
  79     registered with
  80     <citerefentry><refentrytitle>systemd-machined</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  81     are found in <filename>machine.slice</filename>, and user sessions
  82     handled by
  83     <citerefentry><refentrytitle>systemd-logind</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  84     in <filename>user.slice</filename>. See
  85     <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  86     for more information.</para>
  87
  88     <para>See
  89     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  90     for the common options of all unit configuration
  91     files. The common configuration items are configured
  92     in the generic [Unit] and [Install] sections. The
  93     slice specific configuration options are configured in
  94     the [Slice] section. Currently, only generic resource control settings
  95     as described in
  96     <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry> are allowed.
  97     </para>
  98
  99     <para>See the <ulink
 100     url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
 101     Control Group Interfaces</ulink> for an introduction on how to make
 102     use of slice units from programs.</para>
 103   </refsect1>
 104
 105   <refsect1>
 106     <title>Automatic Dependencies</title>
 107
 108     <para>Slice units automatically gain dependencies of type
 109     <varname>After=</varname> and <varname>Requires=</varname> on
 110     their immediate parent slice unit.</para>
 111
 112     <para>Unless <varname>DefaultDependencies=false</varname> is used in the <literal>[Unit]</literal> section, slice
 113     units will implicitly have dependencies of type <varname>Conflicts=</varname> and <varname>Before=</varname> on
 114     <filename>shutdown.target</filename>. These ensure that slice units are removed prior to system shutdown. Only
 115     slice units involved with early boot or late system shutdown should disable this option.
 116     </para>
 117   </refsect1>
 118
 119   <refsect1>
 120     <title>See Also</title>
 121     <para>
 122       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 123       <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 124       <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 125       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 126       <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 127       <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 128       <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 129     </para>
 130   </refsect1>
 131
 132 </refentry>