man/systemd.cgroup.xml

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   9 Copyright 2013 Zbigniew Jędrzejewski-Szmek
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  24
  25 <refentry id="systemd.cgroup">
  26   <refentryinfo>
  27     <title>systemd.cgroup</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>Developer</contrib>
  33         <firstname>Lennart</firstname>
  34         <surname>Poettering</surname>
  35         <email>lennart@poettering.net</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>systemd.cgroup</refentrytitle>
  42     <manvolnum>5</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>systemd.cgroup</refname>
  47     <refpurpose>Cgroup configuration unit settings</refpurpose>
  48   </refnamediv>
  49
  50   <refsynopsisdiv>
  51     <para>
  52       <filename><replaceable>slice</replaceable>.slice</filename>,
  53       <filename><replaceable>scope</replaceable>.scope</filename>,
  54       <filename><replaceable>service</replaceable>.service</filename>,
  55       <filename><replaceable>socket</replaceable>.socket</filename>,
  56       <filename><replaceable>mount</replaceable>.mount</filename>,
  57       <filename><replaceable>swap</replaceable>.swap</filename>
  58     </para>
  59   </refsynopsisdiv>
  60
  61   <refsect1>
  62     <title>Description</title>
  63
  64     <para>Unit configuration files for services, slices, scopes,
  65     sockets, mount points, and swap devices share a subset of
  66     configuration options which configure the control group settings
  67     for spawned processes.</para>
  68
  69     <para>This man page lists the configuration options shared by
  70     those six unit types. See
  71     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  72     for the common options of all unit configuration files, and
  73     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  74     <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  75     <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  76     <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  77     <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  78     and
  79     <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  80     for more information on the specific unit configuration files. The
  81     execution-specific configuration options are configured in the
  82     [Slice], [Scope], [Service], [Socket], [Mount], or [Swap]
  83     sections, depending on the unit type.</para>
  84   </refsect1>
  85
  86   <refsect1>
  87     <title>Options</title>
  88
  89     <para>Units of the types listed above can have settings
  90     for cgroup configuration:</para>
  91
  92     <variablelist class='unit-directives'>
  93       <varlistentry>
  94         <term><varname>CPUAccounting=</varname></term>
  95
  96         <listitem>
  97           <para>Turn on CPU usage accounting for this
  98           unit.</para>
  99         </listitem>
 100       </varlistentry>
 101
 102       <varlistentry>
 103         <term><varname>BlockIOAccounting=</varname></term>
 104
 105         <listitem>
 106           <para>Turn on Block IO bandwidth accounting
 107           for this unit.</para>
 108         </listitem>
 109       </varlistentry>
 110
 111       <varlistentry>
 112         <term><varname>MemoryAccounting=</varname></term>
 113
 114         <listitem>
 115           <para>Turn on process and kernel memory
 116           accounting for this unit.</para>
 117         </listitem>
 118       </varlistentry>
 119
 120
 121       <varlistentry>
 122         <term><varname>CPUShares=<replaceable>weight</replaceable></varname></term>
 123
 124         <listitem>
 125           <para>Assign the specified overall CPU time share weight to
 126           the processes executed. Takes an integer value. This
 127           controls the <literal>cpu.shares</literal> control group
 128           attribute, which defaults to 1024. For details about this
 129           control group attribute, see <ulink
 130           url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para>
 131
 132           <para>Implies <literal>CPUAccounting=true</literal>.</para>
 133         </listitem>
 134       </varlistentry>
 135
 136       <varlistentry>
 137         <term><varname>MemoryLimit=<replaceable>bytes</replaceable></varname></term>
 138         <term><varname>MemorySoftLimit=<replaceable>bytes</replaceable></varname></term>
 139
 140         <listitem>
 141           <para>Specify the hard and soft limits on maximum memory
 142           usage of the executed processes. The "hard" limit specifies
 143           how much process and kernel memory can be used by tasks in
 144           this unit, when there is no memory contention. If the kernel
 145           detects memory contention, memory reclaim will be performed
 146           until the memory usage is within the "soft" limit. Takes a
 147           memory size in bytes. If the value is suffixed with K, M, G
 148           or T, the specified memory size is parsed as Kilobytes,
 149           Megabytes, Gigabytes, or Terabytes (with the base 1024),
 150           respectively. This controls the
 151           <literal>memory.limit_in_bytes</literal> and
 152           <literal>memory.soft_limit_in_bytes</literal> control group
 153           attributes. For details about these control group attributes,
 154           see <ulink
 155           url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para>
 156
 157           <para>Implies <literal>MemoryAccounting=true</literal>.</para>
 158         </listitem>
 159       </varlistentry>
 160
 161       <varlistentry>
 162         <term><varname>BlockIOWeight=<replaceable>weight</replaceable></varname></term>
 163
 164         <listitem><para>Set the default
 165         overall block IO weight for the
 166         executed processes. Takes a single
 167         weight value (between 10 and 1000) to
 168         set the default block IO weight. This
 169         controls the
 170         <literal>blkio.weight</literal>
 171         control group attribute, which
 172         defaults to 1000. For details about
 173         this control group attribute, see
 174         <ulink
 175             url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
 176       </varlistentry>
 177
 178       <varlistentry>
 179         <term><varname>BlockIODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term>
 180
 181         <listitem>
 182           <para>Set the per-device overall block IO weight for the
 183           executed processes. Takes a space-separated pair of a file
 184           path and a weight value to specify the device specific
 185           weight value, between 10 and 1000. (Example: "/dev/sda
 186           500"). The file path may be specified as path to a block
 187           device node or as any other file in which case the backing
 188           block device of the file system of the file is
 189           determined. This controls the
 190           <literal>blkio.weight_device</literal> control group
 191           attribute, which defaults to 1000. Use this option multiple
 192           times to set weights for multiple devices. For details about
 193           this control group attribute, see <ulink
 194           url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para>
 195         </listitem>
 196       </varlistentry>
 197
 198       <varlistentry>
 199         <term><varname>BlockIOReadBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>
 200         <term><varname>BlockIOWriteBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>
 201
 202         <listitem>
 203           <para>Set the per-device overall block IO bandwidth limit
 204           for the executed processes. Takes a space-separated pair of
 205           a file path and a bandwidth value (in bytes per second) to
 206           specify the device specific bandwidth. The file path may be
 207           a path to a block device node, or as any other file in which
 208           case the backing block device of the file system of the file
 209           is used. If the bandwidth is suffixed with K, M, G, or T,
 210           the specified bandwidth is parsed as Kilobytes, Megabytes,
 211           Gigabytes, or Terabytes, respectively (Example:
 212           "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This
 213           controls the <literal>blkio.read_bps_device</literal> and
 214           <literal>blkio.write_bps_device</literal> control group
 215           attributes. Use this option multiple times to set bandwidth
 216           limits for multiple devices. For details about these control
 217           group attributes, see
 218           <ulink url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.
 219           </para>
 220         </listitem>
 221       </varlistentry>
 222
 223       <varlistentry>
 224         <term><varname>DeviceAllow=</varname></term>
 225
 226         <listitem>
 227           <para>Control access to specific device nodes by the
 228           executed processes. Takes two space-separated strings: a
 229           device node path (such as <filename>/dev/null</filename>)
 230           followed by a combination of <constant>r</constant>,
 231           <constant>w</constant>, <constant>m</constant> to control
 232           <emphasis>r</emphasis>eading, <emphasis>w</emphasis>riting,
 233           or creation of the specific device node by the unit
 234           (<emphasis>m</emphasis>knod), respectively. This controls
 235           the <literal>devices.allow</literal> and
 236           <literal>devices.deny</literal> control group
 237           attributes. For details about these control group attributes,
 238           see <ulink
 239           url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para>
 240         </listitem>
 241       </varlistentry>
 242
 243       <varlistentry>
 244         <term><varname>DevicePolicy=auto|closed|strict</varname></term>
 245
 246         <listitem>
 247           <para>
 248             Control the policy for allowing device access:
 249           </para>
 250           <variablelist>
 251             <varlistentry>
 252               <term><option>strict</option></term>
 253               <listitem>
 254                 <para>means to only allow types of access that are
 255                 explicitly specified.</para>
 256               </listitem>
 257             </varlistentry>
 258
 259             <varlistentry>
 260               <term><option>closed</option></term>
 261               <listitem>
 262                 <para>in addition, allows access to standard pseudo
 263                 devices including
 264                 <filename>/dev/null</filename>,
 265                 <filename>/dev/zero</filename>,
 266                 <filename>/dev/full</filename>,
 267                 <filename>/dev/random</filename>, and
 268                 <filename>/dev/urandom</filename>.
 269                 </para>
 270               </listitem>
 271             </varlistentry>
 272
 273             <varlistentry>
 274               <term><option>auto</option></term>
 275               <listitem>
 276                 <para>
 277                   in addition, allows access to all devices if no
 278                   explicit <varname>DeviceAllow=</varname> is present.
 279                   This is the default.
 280                 </para>
 281               </listitem>
 282             </varlistentry>
 283           </variablelist>
 284         </listitem>
 285       </varlistentry>
 286     </variablelist>
 287   </refsect1>
 288
 289   <refsect1>
 290     <title>See Also</title>
 291     <para>
 292       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 293       <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 294       <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 295       <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 296       <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 297       <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 298       <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 299       <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 300       <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 301       The documentation for control groups and specific controllers in the Linux kernel:
 302       <ulink url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>,
 303       <ulink url="http://www.kernel.org/doc/Documentation/cgroups/cpuacct.txt">cpuacct.txt</ulink>,
 304       <ulink url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>,
 305       <ulink url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.
 306     </para>
 307   </refsect1>
 308 </refentry>