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7 This file is part of systemd.
9 Copyright 2013 Zbigniew Jędrzejewski-Szmek
11 systemd is free software; you can redistribute it and/or modify it
12 under the terms of the GNU Lesser General Public License as published by
13 the Free Software Foundation; either version 2.1 of the License, or
14 (at your option) any later version.
16 systemd is distributed in the hope that it will be useful, but
17 WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 Lesser General Public License for more details.
21 You should have received a copy of the GNU Lesser General Public License
22 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 <refentry id="systemd.cgroup">
27 <title>systemd.cgroup</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
41 <refentrytitle>systemd.cgroup</refentrytitle>
42 <manvolnum>5</manvolnum>
46 <refname>systemd.cgroup</refname>
47 <refpurpose>Cgroup configuration unit settings</refpurpose>
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>
62 <title>Description</title>
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>
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>,
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>
87 <title>Options</title>
89 <para>Units of the types listed above can have settings
90 for cgroup configuration:</para>
92 <variablelist class='unit-directives'>
94 <term><varname>CPUAccounting=</varname></term>
97 <para>Turn on the CPU usage accounting for this
103 <term><varname>BlockIOAccounting=</varname></term>
106 <para>Turn on the Block IO bandwidth accounting
107 for this unit.</para>
112 <term><varname>MemoryAccounting=</varname></term>
115 <para>Turn on the process and kernel memory
116 accounting for this unit.</para>
122 <term><varname>CPUShares=<replaceable>weight</replaceable></varname></term>
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>
132 <para>Implies <literal>CPUAccounting=true</literal>.</para>
137 <term><varname>MemoryLimit=<replaceable>bytes</replaceable></varname></term>
138 <term><varname>MemorySoftLimit=<replaceable>bytes</replaceable></varname></term>
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
155 url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para>
157 <para>Implies <literal>MemoryAccounting=true</literal>.</para>
162 <term><varname>BlockIOWeight=<replaceable>weight</replaceable></varname></term>
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
170 <literal>blkio.weight</literal>
171 control group attribute, which
172 defaults to 1000. For details about
173 this control group attribute see
175 url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
179 <term><varname>BlockIODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term>
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>
199 <term><varname>BlockIOReadBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>
200 <term><varname>BlockIOWriteBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term>
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
218 <ulink url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.
224 <term><varname>DeviceAllow=</varname></term>
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 creating 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
239 url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para>
244 <term><varname>DevicePolicy=auto|closed|strict</varname></term>
248 Control the policy for allowing device access:
252 <term><option>strict</option></term>
254 <para>means to only allow types of access that are
255 explicitly specified.</para>
260 <term><option>closed</option></term>
262 <para>in addition allows access to standard pseudo
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>.
274 <term><option>auto</option></term>
277 in addition allows access to all devices if no
278 explicit <varname>DeviceAllow=</varname> is present.
290 <title>See Also</title>
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>.