man/systemd-system.conf.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
   4 <!ENTITY % entities SYSTEM "custom-entities.ent" >
   5 %entities;
   6 ]>
   7 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   8
   9 <refentry id="systemd-system.conf"
  10     xmlns:xi="http://www.w3.org/2001/XInclude">
  11   <refentryinfo>
  12     <title>systemd-system.conf</title>
  13     <productname>systemd</productname>
  14   </refentryinfo>
  15
  16   <refmeta>
  17     <refentrytitle>systemd-system.conf</refentrytitle>
  18     <manvolnum>5</manvolnum>
  19   </refmeta>
  20
  21   <refnamediv>
  22     <refname>systemd-system.conf</refname>
  23     <refname>system.conf.d</refname>
  24     <refname>systemd-user.conf</refname>
  25     <refname>user.conf.d</refname>
  26     <refpurpose>System and session service manager configuration files</refpurpose>
  27   </refnamediv>
  28
  29   <refsynopsisdiv>
  30     <para><filename>/etc/systemd/system.conf</filename>,
  31     <filename>/etc/systemd/system.conf.d/*.conf</filename>,
  32     <filename>/run/systemd/system.conf.d/*.conf</filename>,
  33     <filename>/usr/lib/systemd/system.conf.d/*.conf</filename></para>
  34     <para><filename>/etc/systemd/user.conf</filename>,
  35     <filename>/etc/systemd/user.conf.d/*.conf</filename>,
  36     <filename>/run/systemd/user.conf.d/*.conf</filename>,
  37     <filename>/usr/lib/systemd/user.conf.d/*.conf</filename></para>
  38   </refsynopsisdiv>
  39
  40   <refsect1>
  41     <title>Description</title>
  42
  43     <para>When run as a system instance, systemd interprets the
  44     configuration file <filename>system.conf</filename> and the files
  45     in <filename>system.conf.d</filename> directories; when run as a
  46     user instance, systemd interprets the configuration file
  47     <filename>user.conf</filename> and the files in
  48     <filename>user.conf.d</filename> directories. These configuration
  49     files contain a few settings controlling basic manager
  50     operations. See
  51     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  52     for a general description of the syntax.</para>
  53   </refsect1>
  54
  55   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  56
  57   <refsect1>
  58     <title>Options</title>
  59
  60     <para>All options are configured in the
  61     <literal>[Manager]</literal> section:</para>
  62
  63     <variablelist class='config-directives'>
  64
  65       <varlistentry>
  66         <term><varname>LogLevel=</varname></term>
  67         <term><varname>LogTarget=</varname></term>
  68         <term><varname>LogColor=</varname></term>
  69         <term><varname>LogLocation=</varname></term>
  70         <term><varname>DumpCore=yes</varname></term>
  71         <term><varname>CrashChangeVT=no</varname></term>
  72         <term><varname>CrashShell=no</varname></term>
  73         <term><varname>CrashReboot=no</varname></term>
  74         <term><varname>ShowStatus=yes</varname></term>
  75         <term><varname>DefaultStandardOutput=journal</varname></term>
  76         <term><varname>DefaultStandardError=inherit</varname></term>
  77
  78         <listitem><para>Configures various parameters of basic manager operation. These options may be overridden by
  79         the respective process and kernel command line arguments. See
  80         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
  81         details.</para></listitem>
  82       </varlistentry>
  83
  84       <varlistentry>
  85         <term><varname>CtrlAltDelBurstAction=</varname></term>
  86
  87         <listitem><para>Defines what action will be performed
  88         if user presses Ctrl-Alt-Delete more than 7 times in 2s.
  89         Can be set to <literal>reboot-force</literal>, <literal>poweroff-force</literal>,
  90         <literal>reboot-immediate</literal>, <literal>poweroff-immediate</literal>
  91         or disabled with <literal>none</literal>. Defaults to
  92         <literal>reboot-force</literal>.
  93         </para></listitem>
  94       </varlistentry>
  95
  96       <varlistentry>
  97         <term><varname>CPUAffinity=</varname></term>
  98
  99         <listitem><para>Configures the CPU affinity for the service manager as well as the default CPU
 100         affinity for all forked off processes. Takes a list of CPU indices or ranges separated by either
 101         whitespace or commas. CPU ranges are specified by the lower and upper CPU indices separated by a
 102         dash. This option may be specified more than once, in which case the specified CPU affinity masks are
 103         merged. If the empty string is assigned, the mask is reset, all assignments prior to this will have
 104         no effect. Individual services may override the CPU affinity for their processes with the
 105         <varname>CPUAffinity=</varname> setting in unit files, see
 106         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
 107       </varlistentry>
 108
 109       <varlistentry>
 110         <term><varname>RuntimeWatchdogSec=</varname></term>
 111         <term><varname>ShutdownWatchdogSec=</varname></term>
 112
 113         <listitem><para>Configure the hardware watchdog at runtime and at reboot. Takes a timeout value in seconds (or
 114         in other time units if suffixed with <literal>ms</literal>, <literal>min</literal>, <literal>h</literal>,
 115         <literal>d</literal>, <literal>w</literal>). If <varname>RuntimeWatchdogSec=</varname> is set to a non-zero
 116         value, the watchdog hardware (<filename>/dev/watchdog</filename> or the path specified with
 117         <varname>WatchdogDevice=</varname> or the kernel option <varname>systemd.watchdog-device=</varname>) will be
 118         programmed to automatically reboot the system if it is not contacted within the specified timeout interval. The
 119         system manager will ensure to contact it at least once in half the specified timeout interval. This feature
 120         requires a hardware watchdog device to be present, as it is commonly the case in embedded and server
 121         systems. Not all hardware watchdogs allow configuration of all possible reboot timeout values, in which case
 122         the closest available timeout is picked. <varname>ShutdownWatchdogSec=</varname> may be used to configure the
 123         hardware watchdog when the system is asked to reboot. It works as a safety net to ensure that the reboot takes
 124         place even if a clean reboot attempt times out. Note that the <varname>ShutdownWatchdogSec=</varname> timeout
 125         applies only to the second phase of the reboot, i.e. after all regular services are already terminated, and
 126         after the system and service manager process (PID 1) got replaced by the <filename>systemd-shutdown</filename>
 127         binary, see system <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 128         for details. During the first phase of the shutdown operation the system and service manager remains running
 129         and hence <varname>RuntimeWatchdogSec=</varname> is still honoured. In order to define a timeout on this first
 130         phase of system shutdown, configure <varname>JobTimeoutSec=</varname> and <varname>JobTimeoutAction=</varname>
 131         in the <literal>[Unit]</literal> section of the <filename>shutdown.target</filename> unit. By default
 132         <varname>RuntimeWatchdogSec=</varname> defaults to 0 (off), and <varname>ShutdownWatchdogSec=</varname> to
 133         10min. These settings have no effect if a hardware watchdog is not available.</para></listitem>
 134       </varlistentry>
 135
 136       <varlistentry>
 137         <term><varname>WatchdogDevice=</varname></term>
 138
 139         <listitem><para>Configure the hardware watchdog device that the
 140         runtime and shutdown watchdog timers will open and use. Defaults
 141         to <filename>/dev/watchdog</filename>. This setting has no
 142         effect if a hardware watchdog is not available.</para></listitem>
 143       </varlistentry>
 144
 145       <varlistentry>
 146         <term><varname>CapabilityBoundingSet=</varname></term>
 147
 148         <listitem><para>Controls which capabilities to include in the
 149         capability bounding set for PID 1 and its children. See
 150         <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 151         for details. Takes a whitespace-separated list of capability
 152         names as read by
 153         <citerefentry project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 154         Capabilities listed will be included in the bounding set, all
 155         others are removed. If the list of capabilities is prefixed
 156         with ~, all but the listed capabilities will be included, the
 157         effect of the assignment inverted. Note that this option also
 158         affects the respective capabilities in the effective,
 159         permitted and inheritable capability sets. The capability
 160         bounding set may also be individually configured for units
 161         using the <varname>CapabilityBoundingSet=</varname> directive
 162         for units, but note that capabilities dropped for PID 1 cannot
 163         be regained in individual units, they are lost for
 164         good.</para></listitem>
 165       </varlistentry>
 166
 167       <varlistentry>
 168         <term><varname>NoNewPrivileges=</varname></term>
 169
 170         <listitem><para>Takes a boolean argument. If true, ensures that PID 1
 171         and all its children can never gain new privileges through
 172         <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 173         (e.g. via setuid or setgid bits, or filesystem capabilities).
 174         Defaults to false. General purpose distributions commonly rely
 175         on executables with setuid or setgid bits and will thus not
 176         function properly with this option enabled. Individual units
 177         cannot disable this option.
 178         Also see <ulink url="https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html">No New Privileges Flag</ulink>.
 179         </para></listitem>
 180       </varlistentry>
 181
 182       <varlistentry>
 183         <term><varname>SystemCallArchitectures=</varname></term>
 184
 185         <listitem><para>Takes a space-separated list of architecture
 186         identifiers. Selects from which architectures system calls may
 187         be invoked on this system. This may be used as an effective
 188         way to disable invocation of non-native binaries system-wide,
 189         for example to prohibit execution of 32-bit x86 binaries on
 190         64-bit x86-64 systems. This option operates system-wide, and
 191         acts similar to the
 192         <varname>SystemCallArchitectures=</varname> setting of unit
 193         files, see
 194         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 195         for details. This setting defaults to the empty list, in which
 196         case no filtering of system calls based on architecture is
 197         applied. Known architecture identifiers are
 198         <literal>x86</literal>, <literal>x86-64</literal>,
 199         <literal>x32</literal>, <literal>arm</literal> and the special
 200         identifier <literal>native</literal>. The latter implicitly
 201         maps to the native architecture of the system (or more
 202         specifically, the architecture the system manager was compiled
 203         for). Set this setting to <literal>native</literal> to
 204         prohibit execution of any non-native binaries. When a binary
 205         executes a system call of an architecture that is not listed
 206         in this setting, it will be immediately terminated with the
 207         SIGSYS signal.</para></listitem>
 208       </varlistentry>
 209
 210       <varlistentry>
 211         <term><varname>TimerSlackNSec=</varname></term>
 212
 213         <listitem><para>Sets the timer slack in nanoseconds for PID 1,
 214         which is inherited by all executed processes, unless
 215         overridden individually, for example with the
 216         <varname>TimerSlackNSec=</varname> setting in service units
 217         (for details see
 218         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
 219         The timer slack controls the accuracy of wake-ups triggered by
 220         system timers. See
 221         <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 222         for more information. Note that in contrast to most other time
 223         span definitions this parameter takes an integer value in
 224         nano-seconds if no unit is specified. The usual time units are
 225         understood too.</para></listitem>
 226       </varlistentry>
 227
 228       <varlistentry>
 229         <term><varname>DefaultTimerAccuracySec=</varname></term>
 230
 231         <listitem><para>Sets the default accuracy of timer units. This
 232         controls the global default for the
 233         <varname>AccuracySec=</varname> setting of timer units, see
 234         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 235         for details. <varname>AccuracySec=</varname> set in individual
 236         units override the global default for the specific unit.
 237         Defaults to 1min. Note that the accuracy of timer units is
 238         also affected by the configured timer slack for PID 1, see
 239         <varname>TimerSlackNSec=</varname> above.</para></listitem>
 240       </varlistentry>
 241
 242       <varlistentry>
 243         <term><varname>DefaultTimeoutStartSec=</varname></term>
 244         <term><varname>DefaultTimeoutStopSec=</varname></term>
 245         <term><varname>DefaultTimeoutAbortSec=</varname></term>
 246         <term><varname>DefaultRestartSec=</varname></term>
 247
 248         <listitem><para>Configures the default timeouts for starting,
 249         stopping and aborting of units, as well as the default time to sleep
 250         between automatic restarts of units, as configured per-unit in
 251         <varname>TimeoutStartSec=</varname>,
 252         <varname>TimeoutStopSec=</varname>,
 253         <varname>TimeoutAbortSec=</varname> and
 254         <varname>RestartSec=</varname> (for services, see
 255         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 256         for details on the per-unit settings). Disabled by default, when
 257         service with <varname>Type=oneshot</varname> is used.
 258         For non-service units,
 259         <varname>DefaultTimeoutStartSec=</varname> sets the default
 260         <varname>TimeoutSec=</varname>
 261         value. <varname>DefaultTimeoutStartSec=</varname> and
 262         <varname>DefaultTimeoutStopSec=</varname> default to
 263         90s. <varname>DefaultTimeoutAbortSec=</varname> is not set by default
 264         so that all units fall back to <varname>TimeoutStopSec=</varname>.
 265         <varname>DefaultRestartSec=</varname> defaults to
 266         100ms.</para></listitem>
 267       </varlistentry>
 268
 269       <varlistentry>
 270         <term><varname>DefaultStartLimitIntervalSec=</varname></term>
 271         <term><varname>DefaultStartLimitBurst=</varname></term>
 272
 273         <listitem><para>Configure the default unit start rate
 274         limiting, as configured per-service by
 275         <varname>StartLimitIntervalSec=</varname> and
 276         <varname>StartLimitBurst=</varname>. See
 277         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 278         for details on the per-service settings.
 279         <varname>DefaultStartLimitIntervalSec=</varname> defaults to
 280         10s. <varname>DefaultStartLimitBurst=</varname> defaults to
 281         5.</para></listitem>
 282       </varlistentry>
 283
 284       <varlistentry>
 285         <term><varname>DefaultEnvironment=</varname></term>
 286
 287         <listitem><para>Sets manager environment variables passed to
 288         all executed processes. Takes a space-separated list of
 289         variable assignments. See
 290         <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 291         for details about environment variables.</para>
 292
 293         <para>Example:
 294
 295         <programlisting>DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</programlisting>
 296
 297         Sets three variables
 298         <literal>VAR1</literal>,
 299         <literal>VAR2</literal>,
 300         <literal>VAR3</literal>.</para></listitem>
 301       </varlistentry>
 302
 303       <varlistentry>
 304         <term><varname>DefaultCPUAccounting=</varname></term>
 305         <term><varname>DefaultBlockIOAccounting=</varname></term>
 306         <term><varname>DefaultMemoryAccounting=</varname></term>
 307         <term><varname>DefaultTasksAccounting=</varname></term>
 308         <term><varname>DefaultIOAccounting=</varname></term>
 309         <term><varname>DefaultIPAccounting=</varname></term>
 310
 311         <listitem><para>Configure the default resource accounting settings, as configured per-unit by
 312         <varname>CPUAccounting=</varname>, <varname>BlockIOAccounting=</varname>, <varname>MemoryAccounting=</varname>,
 313         <varname>TasksAccounting=</varname>, <varname>IOAccounting=</varname> and <varname>IPAccounting=</varname>. See
 314         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 315         for details on the per-unit settings. <varname>DefaultTasksAccounting=</varname> defaults to yes,
 316         <varname>DefaultMemoryAccounting=</varname> to &MEMORY_ACCOUNTING_DEFAULT;. <varname>DefaultCPUAccounting=</varname>
 317         defaults to yes if enabling CPU accounting doesn't require the CPU controller to be enabled (Linux 4.15+ using the
 318         unified hierarchy for resource control), otherwise it defaults to no. The other three settings default to no.</para></listitem>
 319       </varlistentry>
 320
 321       <varlistentry>
 322         <term><varname>DefaultTasksMax=</varname></term>
 323
 324         <listitem><para>Configure the default value for the per-unit <varname>TasksMax=</varname> setting. See
 325         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 326         for details. This setting applies to all unit types that support resource control settings, with the exception
 327         of slice units. Defaults to 15%, which equals 4915 with the kernel's defaults on the host, but might be smaller
 328         in OS containers.</para></listitem>
 329       </varlistentry>
 330
 331       <varlistentry>
 332         <term><varname>DefaultLimitCPU=</varname></term>
 333         <term><varname>DefaultLimitFSIZE=</varname></term>
 334         <term><varname>DefaultLimitDATA=</varname></term>
 335         <term><varname>DefaultLimitSTACK=</varname></term>
 336         <term><varname>DefaultLimitCORE=</varname></term>
 337         <term><varname>DefaultLimitRSS=</varname></term>
 338         <term><varname>DefaultLimitNOFILE=</varname></term>
 339         <term><varname>DefaultLimitAS=</varname></term>
 340         <term><varname>DefaultLimitNPROC=</varname></term>
 341         <term><varname>DefaultLimitMEMLOCK=</varname></term>
 342         <term><varname>DefaultLimitLOCKS=</varname></term>
 343         <term><varname>DefaultLimitSIGPENDING=</varname></term>
 344         <term><varname>DefaultLimitMSGQUEUE=</varname></term>
 345         <term><varname>DefaultLimitNICE=</varname></term>
 346         <term><varname>DefaultLimitRTPRIO=</varname></term>
 347         <term><varname>DefaultLimitRTTIME=</varname></term>
 348
 349         <listitem><para>These settings control various default
 350         resource limits for units. See
 351         <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 352         for details. The resource limit is possible to specify in two formats,
 353         <option>value</option> to set soft and hard limits to the same value,
 354         or <option>soft:hard</option> to set both limits individually (e.g. DefaultLimitAS=4G:16G).
 355         Use the string <varname>infinity</varname> to
 356         configure no limit on a specific resource. The multiplicative
 357         suffixes K (=1024), M (=1024*1024) and so on for G, T, P and E
 358         may be used for resource limits measured in bytes
 359         (e.g. DefaultLimitAS=16G). For the limits referring to time values,
 360         the usual time units ms, s, min, h and so on may be used (see
 361         <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 362         for details). Note that if no time unit is specified for
 363         <varname>DefaultLimitCPU=</varname> the default unit of seconds is
 364         implied, while for <varname>DefaultLimitRTTIME=</varname> the default
 365         unit of microseconds is implied. Also, note that the effective
 366         granularity of the limits might influence their
 367         enforcement. For example, time limits specified for
 368         <varname>DefaultLimitCPU=</varname> will be rounded up implicitly to
 369         multiples of 1s. These  settings may be overridden in individual units
 370         using the corresponding LimitXXX= directives. Note that these resource
 371         limits are only defaults for units, they are not applied to PID 1
 372         itself.</para></listitem>
 373       </varlistentry>
 374
 375       <varlistentry>
 376         <term><varname>DefaultOOMPolicy=</varname></term>
 377
 378         <listitem><para>Configure the default policy for reacting to processes being killed by the Linux
 379         Out-Of-Memory (OOM) killer. This may be used to pick a global default for the per-unit
 380         <varname>OOMPolicy=</varname> setting. See
 381         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 382         for details. Note that this default is not used for services that have <varname>Delegate=</varname>
 383         turned on.</para></listitem>
 384       </varlistentry>
 385     </variablelist>
 386   </refsect1>
 387
 388   <refsect1>
 389       <title>See Also</title>
 390       <para>
 391         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 392         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 393         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 394         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 395         <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 396         <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 397       </para>
 398   </refsect1>
 399
 400 </refentry>