man/systemd-system.conf.xml

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  11   This file is part of systemd.
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  13   Copyright 2010 Lennart Poettering
  14
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  28
  29 <refentry id="systemd-system.conf"
  30     xmlns:xi="http://www.w3.org/2001/XInclude">
  31   <refentryinfo>
  32     <title>systemd-system.conf</title>
  33     <productname>systemd</productname>
  34
  35     <authorgroup>
  36       <author>
  37         <contrib>Developer</contrib>
  38         <firstname>Lennart</firstname>
  39         <surname>Poettering</surname>
  40         <email>lennart@poettering.net</email>
  41       </author>
  42     </authorgroup>
  43   </refentryinfo>
  44
  45   <refmeta>
  46     <refentrytitle>systemd-system.conf</refentrytitle>
  47     <manvolnum>5</manvolnum>
  48   </refmeta>
  49
  50   <refnamediv>
  51     <refname>systemd-system.conf</refname>
  52     <refname>system.conf.d</refname>
  53     <refname>systemd-user.conf</refname>
  54     <refname>user.conf.d</refname>
  55     <refpurpose>System and session service manager configuration files</refpurpose>
  56   </refnamediv>
  57
  58   <refsynopsisdiv>
  59     <para><filename>/etc/systemd/system.conf</filename>,
  60     <filename>/etc/systemd/system.conf.d/*.conf</filename>,
  61     <filename>/run/systemd/system.conf.d/*.conf</filename>,
  62     <filename>/usr/lib/systemd/system.conf.d/*.conf</filename></para>
  63     <para><filename>/etc/systemd/user.conf</filename>,
  64     <filename>/etc/systemd/user.conf.d/*.conf</filename>,
  65     <filename>/run/systemd/user.conf.d/*.conf</filename>,
  66     <filename>/usr/lib/systemd/user.conf.d/*.conf</filename></para>
  67   </refsynopsisdiv>
  68
  69   <refsect1>
  70     <title>Description</title>
  71
  72     <para>When run as a system instance, systemd interprets the
  73     configuration file <filename>system.conf</filename> and the files
  74     in <filename>system.conf.d</filename> directories; when run as a
  75     user instance, systemd interprets the configuration file
  76     <filename>user.conf</filename> and the files in
  77     <filename>user.conf.d</filename> directories. These configuration
  78     files contain a few settings controlling basic manager
  79     operations.</para>
  80   </refsect1>
  81
  82   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  83
  84   <refsect1>
  85     <title>Options</title>
  86
  87     <para>All options are configured in the
  88     <literal>[Manager]</literal> section:</para>
  89
  90     <variablelist class='systemd-directives'>
  91
  92       <varlistentry>
  93         <term><varname>LogLevel=</varname></term>
  94         <term><varname>LogTarget=</varname></term>
  95         <term><varname>LogColor=</varname></term>
  96         <term><varname>LogLocation=</varname></term>
  97         <term><varname>DumpCore=yes</varname></term>
  98         <term><varname>CrashChangeVT=no</varname></term>
  99         <term><varname>CrashShell=no</varname></term>
 100         <term><varname>CrashReboot=no</varname></term>
 101         <term><varname>ShowStatus=yes</varname></term>
 102         <term><varname>DefaultStandardOutput=journal</varname></term>
 103         <term><varname>DefaultStandardError=inherit</varname></term>
 104
 105         <listitem><para>Configures various parameters of basic manager operation. These options may be overridden by
 106         the respective process and kernel command line arguments. See
 107         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
 108         details.</para></listitem>
 109       </varlistentry>
 110
 111       <varlistentry>
 112         <term><varname>CtrlAltDelBurstAction=</varname></term>
 113
 114         <listitem><para>Defines what action will be performed
 115         if user presses Ctrl-Alt-Delete more than 7 times in 2s.
 116         Can be set to <literal>reboot-force</literal>, <literal>poweroff-force</literal>,
 117         <literal>reboot-immediate</literal>, <literal>poweroff-immediate</literal>
 118         or disabled with <literal>none</literal>. Defaults to
 119         <literal>reboot-force</literal>.
 120         </para></listitem>
 121       </varlistentry>
 122
 123       <varlistentry>
 124         <term><varname>CPUAffinity=</varname></term>
 125
 126         <listitem><para>Configures the initial CPU affinity for the
 127         init process. Takes a list of CPU indices or ranges separated
 128         by either whitespace or commas. CPU ranges are specified by
 129         the lower and upper CPU indices separated by a
 130         dash.</para></listitem>
 131       </varlistentry>
 132
 133       <varlistentry>
 134         <term><varname>JoinControllers=cpu,cpuacct net_cls,netprio</varname></term>
 135
 136         <listitem><para>Configures controllers that shall be mounted
 137         in a single hierarchy. By default, systemd will mount all
 138         controllers which are enabled in the kernel in individual
 139         hierarchies, with the exception of those listed in this
 140         setting. Takes a space-separated list of comma-separated
 141         controller names, in order to allow multiple joined
 142         hierarchies. Defaults to 'cpu,cpuacct'. Pass an empty string
 143         to ensure that systemd mounts all controllers in separate
 144         hierarchies.</para>
 145
 146         <para>Note that this option is only applied once, at very
 147         early boot. If you use an initial RAM disk (initrd) that uses
 148         systemd, it might hence be necessary to rebuild the initrd if
 149         this option is changed, and make sure the new configuration
 150         file is included in it. Otherwise, the initrd might mount the
 151         controller hierarchies in a different configuration than
 152         intended, and the main system cannot remount them
 153         anymore.</para></listitem>
 154       </varlistentry>
 155
 156       <varlistentry>
 157         <term><varname>RuntimeWatchdogSec=</varname></term>
 158         <term><varname>ShutdownWatchdogSec=</varname></term>
 159
 160         <listitem><para>Configure the hardware watchdog at runtime and at reboot. Takes a timeout value in seconds (or
 161         in other time units if suffixed with <literal>ms</literal>, <literal>min</literal>, <literal>h</literal>,
 162         <literal>d</literal>, <literal>w</literal>). If <varname>RuntimeWatchdogSec=</varname> is set to a non-zero
 163         value, the watchdog hardware (<filename>/dev/watchdog</filename> or the path specified with
 164         <varname>WatchdogDevice=</varname> or the kernel option <varname>systemd.watchdog-device=</varname>) will be
 165         programmed to automatically reboot the system if it is not contacted within the specified timeout interval. The
 166         system manager will ensure to contact it at least once in half the specified timeout interval. This feature
 167         requires a hardware watchdog device to be present, as it is commonly the case in embedded and server
 168         systems. Not all hardware watchdogs allow configuration of all possible reboot timeout values, in which case
 169         the closest available timeout is picked. <varname>ShutdownWatchdogSec=</varname> may be used to configure the
 170         hardware watchdog when the system is asked to reboot. It works as a safety net to ensure that the reboot takes
 171         place even if a clean reboot attempt times out. Note that the <varname>ShutdownWatchdogSec=</varname> timeout
 172         applies only to the second phase of the reboot, i.e. after all regular services are already terminated, and
 173         after the system and service manager process (PID 1) got replaced by the <filename>systemd-shutdown</filename>
 174         binary, see system <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 175         for details. During the first phase of the shutdown operation the system and service manager remains running
 176         and hence <varname>RuntimeWatchdogSec=</varname> is still honoured. In order to define a timeout on this first
 177         phase of system shutdown, configure <varname>JobTimeoutSec=</varname> and <varname>JobTimeoutAction=</varname>
 178         in the <literal>[Unit]</literal> section of the <filename>shutdown.target</filename> unit. By default
 179         <varname>RuntimeWatchdogSec=</varname> defaults to 0 (off), and <varname>ShutdownWatchdogSec=</varname> to
 180         10min. These settings have no effect if a hardware watchdog is not available.</para></listitem>
 181       </varlistentry>
 182
 183       <varlistentry>
 184         <term><varname>WatchdogDevice=</varname></term>
 185
 186         <listitem><para>Configure the hardware watchdog device that the
 187         runtime and shutdown watchdog timers will open and use. Defaults
 188         to <filename>/dev/watchdog</filename>. This setting has no
 189         effect if a hardware watchdog is not available.</para></listitem>
 190       </varlistentry>
 191
 192       <varlistentry>
 193         <term><varname>CapabilityBoundingSet=</varname></term>
 194
 195         <listitem><para>Controls which capabilities to include in the
 196         capability bounding set for PID 1 and its children. See
 197         <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 198         for details. Takes a whitespace-separated list of capability
 199         names as read by
 200         <citerefentry project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 201         Capabilities listed will be included in the bounding set, all
 202         others are removed. If the list of capabilities is prefixed
 203         with ~, all but the listed capabilities will be included, the
 204         effect of the assignment inverted. Note that this option also
 205         affects the respective capabilities in the effective,
 206         permitted and inheritable capability sets. The capability
 207         bounding set may also be individually configured for units
 208         using the <varname>CapabilityBoundingSet=</varname> directive
 209         for units, but note that capabilities dropped for PID 1 cannot
 210         be regained in individual units, they are lost for
 211         good.</para></listitem>
 212       </varlistentry>
 213
 214       <varlistentry>
 215         <term><varname>NoNewPrivileges=</varname></term>
 216
 217         <listitem><para>Takes a boolean argument. If true, ensures that PID 1
 218         and all its children can never gain new privileges through
 219         <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 220         (e.g. via setuid or setgid bits, or filesystem capabilities).
 221         Defaults to false. General purpose distributions commonly rely
 222         on executables with setuid or setgid bits and will thus not
 223         function properly with this option enabled. Individual units
 224         cannot disable this option.
 225         Also see <ulink url="https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html">No New Privileges Flag</ulink>.
 226         </para></listitem>
 227       </varlistentry>
 228
 229       <varlistentry>
 230         <term><varname>SystemCallArchitectures=</varname></term>
 231
 232         <listitem><para>Takes a space-separated list of architecture
 233         identifiers. Selects from which architectures system calls may
 234         be invoked on this system. This may be used as an effective
 235         way to disable invocation of non-native binaries system-wide,
 236         for example to prohibit execution of 32-bit x86 binaries on
 237         64-bit x86-64 systems. This option operates system-wide, and
 238         acts similar to the
 239         <varname>SystemCallArchitectures=</varname> setting of unit
 240         files, see
 241         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 242         for details. This setting defaults to the empty list, in which
 243         case no filtering of system calls based on architecture is
 244         applied. Known architecture identifiers are
 245         <literal>x86</literal>, <literal>x86-64</literal>,
 246         <literal>x32</literal>, <literal>arm</literal> and the special
 247         identifier <literal>native</literal>. The latter implicitly
 248         maps to the native architecture of the system (or more
 249         specifically, the architecture the system manager was compiled
 250         for). Set this setting to <literal>native</literal> to
 251         prohibit execution of any non-native binaries. When a binary
 252         executes a system call of an architecture that is not listed
 253         in this setting, it will be immediately terminated with the
 254         SIGSYS signal.</para></listitem>
 255       </varlistentry>
 256
 257       <varlistentry>
 258         <term><varname>TimerSlackNSec=</varname></term>
 259
 260         <listitem><para>Sets the timer slack in nanoseconds for PID 1,
 261         which is inherited by all executed processes, unless
 262         overridden individually, for example with the
 263         <varname>TimerSlackNSec=</varname> setting in service units
 264         (for details see
 265         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
 266         The timer slack controls the accuracy of wake-ups triggered by
 267         system timers. See
 268         <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 269         for more information. Note that in contrast to most other time
 270         span definitions this parameter takes an integer value in
 271         nano-seconds if no unit is specified. The usual time units are
 272         understood too.</para></listitem>
 273       </varlistentry>
 274
 275       <varlistentry>
 276         <term><varname>DefaultTimerAccuracySec=</varname></term>
 277
 278         <listitem><para>Sets the default accuracy of timer units. This
 279         controls the global default for the
 280         <varname>AccuracySec=</varname> setting of timer units, see
 281         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 282         for details. <varname>AccuracySec=</varname> set in individual
 283         units override the global default for the specific unit.
 284         Defaults to 1min. Note that the accuracy of timer units is
 285         also affected by the configured timer slack for PID 1, see
 286         <varname>TimerSlackNSec=</varname> above.</para></listitem>
 287       </varlistentry>
 288
 289       <varlistentry>
 290         <term><varname>DefaultTimeoutStartSec=</varname></term>
 291         <term><varname>DefaultTimeoutStopSec=</varname></term>
 292         <term><varname>DefaultRestartSec=</varname></term>
 293
 294         <listitem><para>Configures the default timeouts for starting
 295         and stopping of units, as well as the default time to sleep
 296         between automatic restarts of units, as configured per-unit in
 297         <varname>TimeoutStartSec=</varname>,
 298         <varname>TimeoutStopSec=</varname> and
 299         <varname>RestartSec=</varname> (for services, see
 300         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 301         for details on the per-unit settings). For non-service units,
 302         <varname>DefaultTimeoutStartSec=</varname> sets the default
 303         <varname>TimeoutSec=</varname>
 304         value. <varname>DefaultTimeoutStartSec=</varname> and
 305         <varname>DefaultTimeoutStopSec=</varname> default to
 306         90s. <varname>DefaultRestartSec=</varname> defaults to
 307         100ms.</para></listitem>
 308       </varlistentry>
 309
 310       <varlistentry>
 311         <term><varname>DefaultStartLimitIntervalSec=</varname></term>
 312         <term><varname>DefaultStartLimitBurst=</varname></term>
 313
 314         <listitem><para>Configure the default unit start rate
 315         limiting, as configured per-service by
 316         <varname>StartLimitIntervalSec=</varname> and
 317         <varname>StartLimitBurst=</varname>. See
 318         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 319         for details on the per-service settings.
 320         <varname>DefaultStartLimitIntervalSec=</varname> defaults to
 321         10s. <varname>DefaultStartLimitBurst=</varname> defaults to
 322         5.</para></listitem>
 323       </varlistentry>
 324
 325       <varlistentry>
 326         <term><varname>DefaultEnvironment=</varname></term>
 327
 328         <listitem><para>Sets manager environment variables passed to
 329         all executed processes. Takes a space-separated list of
 330         variable assignments. See
 331         <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 332         for details about environment variables.</para>
 333
 334         <para>Example:
 335
 336         <programlisting>DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</programlisting>
 337
 338         Sets three variables
 339         <literal>VAR1</literal>,
 340         <literal>VAR2</literal>,
 341         <literal>VAR3</literal>.</para></listitem>
 342       </varlistentry>
 343
 344       <varlistentry>
 345         <term><varname>DefaultCPUAccounting=</varname></term>
 346         <term><varname>DefaultBlockIOAccounting=</varname></term>
 347         <term><varname>DefaultMemoryAccounting=</varname></term>
 348         <term><varname>DefaultTasksAccounting=</varname></term>
 349         <term><varname>DefaultIPAccounting=</varname></term>
 350
 351         <listitem><para>Configure the default resource accounting settings, as configured per-unit by
 352         <varname>CPUAccounting=</varname>, <varname>BlockIOAccounting=</varname>, <varname>MemoryAccounting=</varname>,
 353         <varname>TasksAccounting=</varname> and <varname>IPAccounting=</varname>. See
 354         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 355         for details on the per-unit settings. <varname>DefaultTasksAccounting=</varname> defaults to on,
 356         <varname>DefaultMemoryAccounting=</varname> to &MEMORY_ACCOUNTING_DEFAULT;,
 357         the other three settings to off.</para></listitem>
 358       </varlistentry>
 359
 360       <varlistentry>
 361         <term><varname>DefaultTasksMax=</varname></term>
 362
 363         <listitem><para>Configure the default value for the per-unit <varname>TasksMax=</varname> setting. See
 364         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 365         for details. This setting applies to all unit types that support resource control settings, with the exception
 366         of slice units. Defaults to 15%, which equals 4915 with the kernel's defaults on the host, but might be smaller
 367         in OS containers.</para></listitem>
 368       </varlistentry>
 369
 370       <varlistentry>
 371         <term><varname>DefaultLimitCPU=</varname></term>
 372         <term><varname>DefaultLimitFSIZE=</varname></term>
 373         <term><varname>DefaultLimitDATA=</varname></term>
 374         <term><varname>DefaultLimitSTACK=</varname></term>
 375         <term><varname>DefaultLimitCORE=</varname></term>
 376         <term><varname>DefaultLimitRSS=</varname></term>
 377         <term><varname>DefaultLimitNOFILE=</varname></term>
 378         <term><varname>DefaultLimitAS=</varname></term>
 379         <term><varname>DefaultLimitNPROC=</varname></term>
 380         <term><varname>DefaultLimitMEMLOCK=</varname></term>
 381         <term><varname>DefaultLimitLOCKS=</varname></term>
 382         <term><varname>DefaultLimitSIGPENDING=</varname></term>
 383         <term><varname>DefaultLimitMSGQUEUE=</varname></term>
 384         <term><varname>DefaultLimitNICE=</varname></term>
 385         <term><varname>DefaultLimitRTPRIO=</varname></term>
 386         <term><varname>DefaultLimitRTTIME=</varname></term>
 387
 388         <listitem><para>These settings control various default
 389         resource limits for units. See
 390         <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 391         for details. The resource limit is possible to specify in two formats,
 392         <option>value</option> to set soft and hard limits to the same value,
 393         or <option>soft:hard</option> to set both limits individually (e.g. DefaultLimitAS=4G:16G).
 394         Use the string <varname>infinity</varname> to
 395         configure no limit on a specific resource. The multiplicative
 396         suffixes K (=1024), M (=1024*1024) and so on for G, T, P and E
 397         may be used for resource limits measured in bytes
 398         (e.g. DefaultLimitAS=16G). For the limits referring to time values,
 399         the usual time units ms, s, min, h and so on may be used (see
 400         <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 401         for details). Note that if no time unit is specified for
 402         <varname>DefaultLimitCPU=</varname> the default unit of seconds is
 403         implied, while for <varname>DefaultLimitRTTIME=</varname> the default
 404         unit of microseconds is implied. Also, note that the effective
 405         granularity of the limits might influence their
 406         enforcement. For example, time limits specified for
 407         <varname>DefaultLimitCPU=</varname> will be rounded up implicitly to
 408         multiples of 1s. These  settings may be overridden in individual units
 409         using the corresponding LimitXXX= directives. Note that these resource
 410         limits are only defaults for units, they are not applied to PID 1
 411         itself.</para></listitem>
 412       </varlistentry>
 413     </variablelist>
 414   </refsect1>
 415
 416   <refsect1>
 417       <title>See Also</title>
 418       <para>
 419         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 420         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 421         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 422         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 423         <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 424         <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 425       </para>
 426   </refsect1>
 427
 428 </refentry>