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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?> | |
3 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
4 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
5 | ||
6 | <!-- | |
7 | This file is part of systemd. | |
8 | ||
9 | Copyright 2013 Zbigniew Jędrzejewski-Szmek | |
10 | ||
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. | |
15 | ||
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. | |
20 | ||
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/>. | |
23 | --> | |
24 | ||
25 | <refentry id="systemd.resource-control"> | |
26 | <refentryinfo> | |
27 | <title>systemd.resource-control</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.resource-control</refentrytitle> | |
42 | <manvolnum>5</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>systemd.resource-control</refname> | |
47 | <refpurpose>Resource control 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 for resource control of spawned | |
60f067b4 | 67 | processes. Internally, this relies on the Control Groups |
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68 | kernel concept for organizing processes in a hierarchial tree of |
69 | named groups for the purpose of resource management.</para> | |
70 | ||
71 | <para>This man page lists the configuration options shared by | |
72 | those six unit types. See | |
73 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
74 | for the common options of all unit configuration files, and | |
75 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
76 | <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
77 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
78 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
79 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
80 | and | |
81 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
82 | for more information on the specific unit configuration files. The | |
83 | resource control configuration options are configured in the | |
84 | [Slice], [Scope], [Service], [Socket], [Mount], or [Swap] | |
85 | sections, depending on the unit type.</para> | |
86 | ||
87 | <para>See the <ulink | |
88 | url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New | |
60f067b4 | 89 | Control Group Interfaces</ulink> for an introduction on how to make |
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90 | use of resource control APIs from programs.</para> |
91 | </refsect1> | |
92 | ||
93 | <refsect1> | |
94 | <title>Options</title> | |
95 | ||
96 | <para>Units of the types listed above can have settings | |
97 | for resource control configuration:</para> | |
98 | ||
99 | <variablelist class='unit-directives'> | |
100 | ||
101 | <varlistentry> | |
102 | <term><varname>CPUAccounting=</varname></term> | |
103 | ||
104 | <listitem> | |
105 | <para>Turn on CPU usage accounting for this unit. Takes a | |
106 | boolean argument. Note that turning on CPU accounting for | |
107 | one unit might also implicitly turn it on for all units | |
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108 | contained in the same slice and for all its parent slices |
109 | and the units contained therein. The system default for this | |
110 | setting maybe controlled with | |
111 | <varname>DefaultCPUAccounting=</varname> in | |
112 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
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113 | </listitem> |
114 | </varlistentry> | |
115 | ||
116 | <varlistentry> | |
117 | <term><varname>CPUShares=<replaceable>weight</replaceable></varname></term> | |
60f067b4 | 118 | <term><varname>StartupCPUShares=<replaceable>weight</replaceable></varname></term> |
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119 | |
120 | <listitem> | |
60f067b4 JS |
121 | <para>Assign the specified CPU time share weight to the |
122 | processes executed. Those options take an integer value and | |
123 | control the <literal>cpu.shares</literal> control group | |
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124 | attribute, which defaults to 1024. For details about this |
125 | control group attribute, see <ulink | |
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126 | url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>. |
127 | The available CPU time is split up among all units within | |
128 | one slice relative to their CPU time share weight.</para> | |
129 | ||
130 | <para>While <varname>StartupCPUShares=</varname> only | |
131 | applies to the startup phase of the system, | |
132 | <varname>CPUShares=</varname> applies to normal runtime of | |
133 | the system, and if the former is not set also to the startup | |
134 | phase. Using <varname>StartupCPUShares=</varname> allows | |
135 | priorizing specific services at boot-up differently than | |
136 | during normal runtime.</para> | |
137 | ||
138 | <para>Those options imply | |
139 | <literal>CPUAccounting=true</literal>.</para> | |
140 | </listitem> | |
141 | </varlistentry> | |
142 | ||
143 | <varlistentry> | |
144 | <term><varname>CPUQuota=</varname></term> | |
145 | ||
146 | <listitem> | |
147 | <para>Assign the specified CPU time quota to the processes | |
148 | executed. Takes a percentage value, suffixed with "%". The | |
149 | percentage specifies how much CPU time the unit shall get at | |
150 | maximum, relative to the total CPU time available on one | |
151 | CPU. Use values > 100% for alloting CPU time on more than | |
152 | one CPU. This controls the | |
153 | <literal>cpu.cfs_quota_us</literal> control group | |
154 | attribute. For details about this control group attribute, | |
155 | see <ulink | |
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156 | url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para> |
157 | ||
60f067b4 JS |
158 | <para>Example: <varname>CPUShares=20%</varname> ensures that |
159 | the executed processes will never get more than 20% CPU time | |
160 | on one CPU.</para> | |
161 | ||
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162 | <para>Implies <literal>CPUAccounting=true</literal>.</para> |
163 | </listitem> | |
164 | </varlistentry> | |
165 | ||
166 | <varlistentry> | |
167 | <term><varname>MemoryAccounting=</varname></term> | |
168 | ||
169 | <listitem> | |
170 | <para>Turn on process and kernel memory accounting for this | |
171 | unit. Takes a boolean argument. Note that turning on memory | |
172 | accounting for one unit might also implicitly turn it on for | |
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173 | all its parent slices. The system default for this setting |
174 | maybe controlled with | |
175 | <varname>DefaultMemoryAccounting=</varname> in | |
176 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
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177 | </listitem> |
178 | </varlistentry> | |
179 | ||
180 | <varlistentry> | |
181 | <term><varname>MemoryLimit=<replaceable>bytes</replaceable></varname></term> | |
182 | ||
183 | <listitem> | |
184 | <para>Specify the limit on maximum memory usage of the | |
185 | executed processes. The limit specifies how much process and | |
186 | kernel memory can be used by tasks in this unit. Takes a | |
187 | memory size in bytes. If the value is suffixed with K, M, G | |
188 | or T, the specified memory size is parsed as Kilobytes, | |
189 | Megabytes, Gigabytes, or Terabytes (with the base 1024), | |
190 | respectively. This controls the | |
191 | <literal>memory.limit_in_bytes</literal> control group | |
192 | attribute. For details about this control group attribute, | |
193 | see <ulink | |
194 | url="https://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para> | |
195 | ||
196 | <para>Implies <literal>MemoryAccounting=true</literal>.</para> | |
197 | </listitem> | |
198 | </varlistentry> | |
199 | ||
200 | <varlistentry> | |
201 | <term><varname>BlockIOAccounting=</varname></term> | |
202 | ||
203 | <listitem> | |
204 | <para>Turn on Block IO accounting for this unit. Takes a | |
205 | boolean argument. Note that turning on block IO accounting | |
206 | for one unit might also implicitly turn it on for all units | |
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207 | contained in the same slice and all for its parent slices |
208 | and the units contained therein. The system default for this | |
209 | setting maybe controlled with | |
210 | <varname>DefaultBlockIOAccounting=</varname> in | |
211 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
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212 | </listitem> |
213 | </varlistentry> | |
214 | ||
215 | <varlistentry> | |
216 | <term><varname>BlockIOWeight=<replaceable>weight</replaceable></varname></term> | |
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217 | <term><varname>StartupBlockIOWeight=<replaceable>weight</replaceable></varname></term> |
218 | ||
219 | <listitem><para>Set the default overall block IO weight for | |
220 | the executed processes. Takes a single weight value (between | |
221 | 10 and 1000) to set the default block IO weight. This controls | |
222 | the <literal>blkio.weight</literal> control group attribute, | |
223 | which defaults to 1000. For details about this control group | |
224 | attribute, see <ulink | |
225 | url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>. | |
226 | The available IO bandwidth is split up among all units within | |
227 | one slice relative to their block IO weight.</para> | |
228 | ||
229 | <para>While <varname>StartupBlockIOWeight=</varname> only | |
230 | applies to the startup phase of the system, | |
231 | <varname>BlockIOWeight=</varname> applies to the later runtime | |
232 | of the system, and if the former is not set also to the | |
233 | startup phase. This allows priorizing specific services at | |
234 | boot-up differently than during runtime.</para> | |
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235 | |
236 | <para>Implies | |
237 | <literal>BlockIOAccounting=true</literal>.</para> | |
238 | </listitem> | |
239 | </varlistentry> | |
240 | ||
241 | <varlistentry> | |
242 | <term><varname>BlockIODeviceWeight=<replaceable>device</replaceable> <replaceable>weight</replaceable></varname></term> | |
243 | ||
244 | <listitem> | |
245 | <para>Set the per-device overall block IO weight for the | |
246 | executed processes. Takes a space-separated pair of a file | |
247 | path and a weight value to specify the device specific | |
248 | weight value, between 10 and 1000. (Example: "/dev/sda | |
249 | 500"). The file path may be specified as path to a block | |
60f067b4 | 250 | device node or as any other file, in which case the backing |
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251 | block device of the file system of the file is |
252 | determined. This controls the | |
253 | <literal>blkio.weight_device</literal> control group | |
254 | attribute, which defaults to 1000. Use this option multiple | |
255 | times to set weights for multiple devices. For details about | |
256 | this control group attribute, see <ulink | |
257 | url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para> | |
258 | ||
259 | <para>Implies | |
260 | <literal>BlockIOAccounting=true</literal>.</para> | |
261 | </listitem> | |
262 | </varlistentry> | |
263 | ||
264 | <varlistentry> | |
265 | <term><varname>BlockIOReadBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term> | |
266 | <term><varname>BlockIOWriteBandwidth=<replaceable>device</replaceable> <replaceable>bytes</replaceable></varname></term> | |
267 | ||
268 | <listitem> | |
269 | <para>Set the per-device overall block IO bandwidth limit | |
270 | for the executed processes. Takes a space-separated pair of | |
271 | a file path and a bandwidth value (in bytes per second) to | |
272 | specify the device specific bandwidth. The file path may be | |
273 | a path to a block device node, or as any other file in which | |
274 | case the backing block device of the file system of the file | |
275 | is used. If the bandwidth is suffixed with K, M, G, or T, | |
276 | the specified bandwidth is parsed as Kilobytes, Megabytes, | |
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277 | Gigabytes, or Terabytes, respectively, to the base of |
278 | 1000. (Example: | |
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279 | "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This |
280 | controls the <literal>blkio.read_bps_device</literal> and | |
281 | <literal>blkio.write_bps_device</literal> control group | |
282 | attributes. Use this option multiple times to set bandwidth | |
283 | limits for multiple devices. For details about these control | |
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284 | group attributes, see <ulink |
285 | url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>. | |
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286 | </para> |
287 | ||
288 | <para>Implies | |
289 | <literal>BlockIOAccounting=true</literal>.</para> | |
290 | </listitem> | |
291 | </varlistentry> | |
292 | ||
293 | <varlistentry> | |
294 | <term><varname>DeviceAllow=</varname></term> | |
295 | ||
296 | <listitem> | |
297 | <para>Control access to specific device nodes by the | |
298 | executed processes. Takes two space-separated strings: a | |
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299 | device node specifier followed by a combination of |
300 | <constant>r</constant>, <constant>w</constant>, | |
301 | <constant>m</constant> to control | |
14228c0d | 302 | <emphasis>r</emphasis>eading, <emphasis>w</emphasis>riting, |
60f067b4 | 303 | or creation of the specific device node(s) by the unit |
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304 | (<emphasis>m</emphasis>knod), respectively. This controls |
305 | the <literal>devices.allow</literal> and | |
306 | <literal>devices.deny</literal> control group | |
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307 | attributes. For details about these control group |
308 | attributes, see <ulink | |
14228c0d | 309 | url="https://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para> |
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310 | |
311 | <para>The device node specifier is either a path to a device | |
312 | node in the file system, starting with | |
313 | <filename>/dev/</filename>, or a string starting with either | |
314 | <literal>char-</literal> or <literal>block-</literal> | |
315 | followed by a device group name, as listed in | |
316 | <filename>/proc/devices</filename>. The latter is useful to | |
317 | whitelist all current and future devices belonging to a | |
318 | specific device group at once. The device group is matched | |
319 | according to file name globbing rules, you may hence use the | |
320 | <literal>*</literal> and <literal>?</literal> | |
321 | wildcards. Examples: <filename>/dev/sda5</filename> is a | |
322 | path to a device node, referring to an ATA or SCSI block | |
323 | device. <literal>char-pts</literal> and | |
324 | <literal>char-alsa</literal> are specifiers for all pseudo | |
325 | TTYs and all ALSA sound devices, | |
326 | respectively. <literal>char-cpu/*</literal> is a specifier | |
327 | matching all CPU related device groups.</para> | |
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328 | </listitem> |
329 | </varlistentry> | |
330 | ||
331 | <varlistentry> | |
332 | <term><varname>DevicePolicy=auto|closed|strict</varname></term> | |
333 | ||
334 | <listitem> | |
335 | <para> | |
336 | Control the policy for allowing device access: | |
337 | </para> | |
338 | <variablelist> | |
339 | <varlistentry> | |
340 | <term><option>strict</option></term> | |
341 | <listitem> | |
342 | <para>means to only allow types of access that are | |
343 | explicitly specified.</para> | |
344 | </listitem> | |
345 | </varlistentry> | |
346 | ||
347 | <varlistentry> | |
348 | <term><option>closed</option></term> | |
349 | <listitem> | |
350 | <para>in addition, allows access to standard pseudo | |
351 | devices including | |
352 | <filename>/dev/null</filename>, | |
353 | <filename>/dev/zero</filename>, | |
354 | <filename>/dev/full</filename>, | |
355 | <filename>/dev/random</filename>, and | |
356 | <filename>/dev/urandom</filename>. | |
357 | </para> | |
358 | </listitem> | |
359 | </varlistentry> | |
360 | ||
361 | <varlistentry> | |
362 | <term><option>auto</option></term> | |
363 | <listitem> | |
364 | <para> | |
365 | in addition, allows access to all devices if no | |
366 | explicit <varname>DeviceAllow=</varname> is present. | |
367 | This is the default. | |
368 | </para> | |
369 | </listitem> | |
370 | </varlistentry> | |
371 | </variablelist> | |
372 | </listitem> | |
373 | </varlistentry> | |
374 | ||
375 | <varlistentry> | |
376 | <term><varname>Slice=</varname></term> | |
377 | ||
378 | <listitem> | |
379 | <para>The name of the slice unit to place the unit | |
380 | in. Defaults to <filename>system.slice</filename> for all | |
381 | non-instantiated units of all unit types (except for slice | |
382 | units themselves see below). Instance units are by default | |
383 | placed in a subslice of <filename>system.slice</filename> | |
384 | that is named after the template name.</para> | |
385 | ||
386 | <para>This option may be used to arrange systemd units in a | |
387 | hierarchy of slices each of which might have resource | |
388 | settings applied.</para> | |
389 | ||
390 | <para>For units of type slice, the only accepted value for | |
391 | this setting is the parent slice. Since the name of a slice | |
392 | unit implies the parent slice, it is hence redundant to ever | |
393 | set this parameter directly for slice units.</para> | |
394 | </listitem> | |
395 | </varlistentry> | |
396 | ||
397 | </variablelist> | |
398 | </refsect1> | |
399 | ||
400 | <refsect1> | |
401 | <title>See Also</title> | |
402 | <para> | |
403 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
404 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
405 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
406 | <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
407 | <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
408 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
409 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
410 | <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
411 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
412 | <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
413 | The documentation for control groups and specific controllers in the Linux kernel: | |
414 | <ulink url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>, | |
415 | <ulink url="https://www.kernel.org/doc/Documentation/cgroups/cpuacct.txt">cpuacct.txt</ulink>, | |
416 | <ulink url="https://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>, | |
417 | <ulink url="https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>. | |
418 | </para> | |
419 | </refsect1> | |
420 | </refentry> |