man/systemd-system.conf.xml

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  12 <refentry id="systemd-system.conf"
  13     xmlns:xi="http://www.w3.org/2001/XInclude">
  14   <refentryinfo>
  15     <title>systemd-system.conf</title>
  16     <productname>systemd</productname>
  17
  18     <authorgroup>
  19       <author>
  20         <contrib>Developer</contrib>
  21         <firstname>Lennart</firstname>
  22         <surname>Poettering</surname>
  23         <email>lennart@poettering.net</email>
  24       </author>
  25     </authorgroup>
  26   </refentryinfo>
  27
  28   <refmeta>
  29     <refentrytitle>systemd-system.conf</refentrytitle>
  30     <manvolnum>5</manvolnum>
  31   </refmeta>
  32
  33   <refnamediv>
  34     <refname>systemd-system.conf</refname>
  35     <refname>system.conf.d</refname>
  36     <refname>systemd-user.conf</refname>
  37     <refname>user.conf.d</refname>
  38     <refpurpose>System and session service manager configuration files</refpurpose>
  39   </refnamediv>
  40
  41   <refsynopsisdiv>
  42     <para><filename>/etc/systemd/system.conf</filename>,
  43     <filename>/etc/systemd/system.conf.d/*.conf</filename>,
  44     <filename>/run/systemd/system.conf.d/*.conf</filename>,
  45     <filename>/usr/lib/systemd/system.conf.d/*.conf</filename></para>
  46     <para><filename>/etc/systemd/user.conf</filename>,
  47     <filename>/etc/systemd/user.conf.d/*.conf</filename>,
  48     <filename>/run/systemd/user.conf.d/*.conf</filename>,
  49     <filename>/usr/lib/systemd/user.conf.d/*.conf</filename></para>
  50   </refsynopsisdiv>
  51
  52   <refsect1>
  53     <title>Description</title>
  54
  55     <para>When run as a system instance, systemd interprets the
  56     configuration file <filename>system.conf</filename> and the files
  57     in <filename>system.conf.d</filename> directories; when run as a
  58     user instance, systemd interprets the configuration file
  59     <filename>user.conf</filename> and the files in
  60     <filename>user.conf.d</filename> directories. These configuration
  61     files contain a few settings controlling basic manager
  62     operations. See
  63     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  64     for a general description of the syntax.</para>
  65   </refsect1>
  66
  67   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  68
  69   <refsect1>
  70     <title>Options</title>
  71
  72     <para>All options are configured in the
  73     <literal>[Manager]</literal> section:</para>
  74
  75     <variablelist class='systemd-directives'>
  76
  77       <varlistentry>
  78         <term><varname>LogLevel=</varname></term>
  79         <term><varname>LogTarget=</varname></term>
  80         <term><varname>LogColor=</varname></term>
  81         <term><varname>LogLocation=</varname></term>
  82         <term><varname>DumpCore=yes</varname></term>
  83         <term><varname>CrashChangeVT=no</varname></term>
  84         <term><varname>CrashShell=no</varname></term>
  85         <term><varname>CrashReboot=no</varname></term>
  86         <term><varname>ShowStatus=yes</varname></term>
  87         <term><varname>DefaultStandardOutput=journal</varname></term>
  88         <term><varname>DefaultStandardError=inherit</varname></term>
  89
  90         <listitem><para>Configures various parameters of basic manager operation. These options may be overridden by
  91         the respective process and kernel command line arguments. See
  92         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
  93         details.</para></listitem>
  94       </varlistentry>
  95
  96       <varlistentry>
  97         <term><varname>CtrlAltDelBurstAction=</varname></term>
  98
  99         <listitem><para>Defines what action will be performed
 100         if user presses Ctrl-Alt-Delete more than 7 times in 2s.
 101         Can be set to <literal>reboot-force</literal>, <literal>poweroff-force</literal>,
 102         <literal>reboot-immediate</literal>, <literal>poweroff-immediate</literal>
 103         or disabled with <literal>none</literal>. Defaults to
 104         <literal>reboot-force</literal>.
 105         </para></listitem>
 106       </varlistentry>
 107
 108       <varlistentry>
 109         <term><varname>CPUAffinity=</varname></term>
 110
 111         <listitem><para>Configures the initial CPU affinity for the
 112         init process. Takes a list of CPU indices or ranges separated
 113         by either whitespace or commas. CPU ranges are specified by
 114         the lower and upper CPU indices separated by a
 115         dash.</para></listitem>
 116       </varlistentry>
 117
 118       <varlistentry>
 119         <term><varname>JoinControllers=cpu,cpuacct net_cls,netprio</varname></term>
 120
 121         <listitem><para>Configures controllers that shall be mounted
 122         in a single hierarchy. By default, systemd will mount all
 123         controllers which are enabled in the kernel in individual
 124         hierarchies, with the exception of those listed in this
 125         setting. Takes a space-separated list of comma-separated
 126         controller names, in order to allow multiple joined
 127         hierarchies. Defaults to 'cpu,cpuacct'. Pass an empty string
 128         to ensure that systemd mounts all controllers in separate
 129         hierarchies.</para>
 130
 131         <para>Note that this option is only applied once, at very
 132         early boot. If you use an initial RAM disk (initrd) that uses
 133         systemd, it might hence be necessary to rebuild the initrd if
 134         this option is changed, and make sure the new configuration
 135         file is included in it. Otherwise, the initrd might mount the
 136         controller hierarchies in a different configuration than
 137         intended, and the main system cannot remount them
 138         anymore.</para></listitem>
 139       </varlistentry>
 140
 141       <varlistentry>
 142         <term><varname>RuntimeWatchdogSec=</varname></term>
 143         <term><varname>ShutdownWatchdogSec=</varname></term>
 144
 145         <listitem><para>Configure the hardware watchdog at runtime and at reboot. Takes a timeout value in seconds (or
 146         in other time units if suffixed with <literal>ms</literal>, <literal>min</literal>, <literal>h</literal>,
 147         <literal>d</literal>, <literal>w</literal>). If <varname>RuntimeWatchdogSec=</varname> is set to a non-zero
 148         value, the watchdog hardware (<filename>/dev/watchdog</filename> or the path specified with
 149         <varname>WatchdogDevice=</varname> or the kernel option <varname>systemd.watchdog-device=</varname>) will be
 150         programmed to automatically reboot the system if it is not contacted within the specified timeout interval. The
 151         system manager will ensure to contact it at least once in half the specified timeout interval. This feature
 152         requires a hardware watchdog device to be present, as it is commonly the case in embedded and server
 153         systems. Not all hardware watchdogs allow configuration of all possible reboot timeout values, in which case
 154         the closest available timeout is picked. <varname>ShutdownWatchdogSec=</varname> may be used to configure the
 155         hardware watchdog when the system is asked to reboot. It works as a safety net to ensure that the reboot takes
 156         place even if a clean reboot attempt times out. Note that the <varname>ShutdownWatchdogSec=</varname> timeout
 157         applies only to the second phase of the reboot, i.e. after all regular services are already terminated, and
 158         after the system and service manager process (PID 1) got replaced by the <filename>systemd-shutdown</filename>
 159         binary, see system <citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 160         for details. During the first phase of the shutdown operation the system and service manager remains running
 161         and hence <varname>RuntimeWatchdogSec=</varname> is still honoured. In order to define a timeout on this first
 162         phase of system shutdown, configure <varname>JobTimeoutSec=</varname> and <varname>JobTimeoutAction=</varname>
 163         in the <literal>[Unit]</literal> section of the <filename>shutdown.target</filename> unit. By default
 164         <varname>RuntimeWatchdogSec=</varname> defaults to 0 (off), and <varname>ShutdownWatchdogSec=</varname> to
 165         10min. These settings have no effect if a hardware watchdog is not available.</para></listitem>
 166       </varlistentry>
 167
 168       <varlistentry>
 169         <term><varname>WatchdogDevice=</varname></term>
 170
 171         <listitem><para>Configure the hardware watchdog device that the
 172         runtime and shutdown watchdog timers will open and use. Defaults
 173         to <filename>/dev/watchdog</filename>. This setting has no
 174         effect if a hardware watchdog is not available.</para></listitem>
 175       </varlistentry>
 176
 177       <varlistentry>
 178         <term><varname>CapabilityBoundingSet=</varname></term>
 179
 180         <listitem><para>Controls which capabilities to include in the
 181         capability bounding set for PID 1 and its children. See
 182         <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 183         for details. Takes a whitespace-separated list of capability
 184         names as read by
 185         <citerefentry project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 186         Capabilities listed will be included in the bounding set, all
 187         others are removed. If the list of capabilities is prefixed
 188         with ~, all but the listed capabilities will be included, the
 189         effect of the assignment inverted. Note that this option also
 190         affects the respective capabilities in the effective,
 191         permitted and inheritable capability sets. The capability
 192         bounding set may also be individually configured for units
 193         using the <varname>CapabilityBoundingSet=</varname> directive
 194         for units, but note that capabilities dropped for PID 1 cannot
 195         be regained in individual units, they are lost for
 196         good.</para></listitem>
 197       </varlistentry>
 198
 199       <varlistentry>
 200         <term><varname>NoNewPrivileges=</varname></term>
 201
 202         <listitem><para>Takes a boolean argument. If true, ensures that PID 1
 203         and all its children can never gain new privileges through
 204         <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 205         (e.g. via setuid or setgid bits, or filesystem capabilities).
 206         Defaults to false. General purpose distributions commonly rely
 207         on executables with setuid or setgid bits and will thus not
 208         function properly with this option enabled. Individual units
 209         cannot disable this option.
 210         Also see <ulink url="https://www.kernel.org/doc/html/latest/userspace-api/no_new_privs.html">No New Privileges Flag</ulink>.
 211         </para></listitem>
 212       </varlistentry>
 213
 214       <varlistentry>
 215         <term><varname>SystemCallArchitectures=</varname></term>
 216
 217         <listitem><para>Takes a space-separated list of architecture
 218         identifiers. Selects from which architectures system calls may
 219         be invoked on this system. This may be used as an effective
 220         way to disable invocation of non-native binaries system-wide,
 221         for example to prohibit execution of 32-bit x86 binaries on
 222         64-bit x86-64 systems. This option operates system-wide, and
 223         acts similar to the
 224         <varname>SystemCallArchitectures=</varname> setting of unit
 225         files, see
 226         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 227         for details. This setting defaults to the empty list, in which
 228         case no filtering of system calls based on architecture is
 229         applied. Known architecture identifiers are
 230         <literal>x86</literal>, <literal>x86-64</literal>,
 231         <literal>x32</literal>, <literal>arm</literal> and the special
 232         identifier <literal>native</literal>. The latter implicitly
 233         maps to the native architecture of the system (or more
 234         specifically, the architecture the system manager was compiled
 235         for). Set this setting to <literal>native</literal> to
 236         prohibit execution of any non-native binaries. When a binary
 237         executes a system call of an architecture that is not listed
 238         in this setting, it will be immediately terminated with the
 239         SIGSYS signal.</para></listitem>
 240       </varlistentry>
 241
 242       <varlistentry>
 243         <term><varname>TimerSlackNSec=</varname></term>
 244
 245         <listitem><para>Sets the timer slack in nanoseconds for PID 1,
 246         which is inherited by all executed processes, unless
 247         overridden individually, for example with the
 248         <varname>TimerSlackNSec=</varname> setting in service units
 249         (for details see
 250         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
 251         The timer slack controls the accuracy of wake-ups triggered by
 252         system timers. See
 253         <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 254         for more information. Note that in contrast to most other time
 255         span definitions this parameter takes an integer value in
 256         nano-seconds if no unit is specified. The usual time units are
 257         understood too.</para></listitem>
 258       </varlistentry>
 259
 260       <varlistentry>
 261         <term><varname>DefaultTimerAccuracySec=</varname></term>
 262
 263         <listitem><para>Sets the default accuracy of timer units. This
 264         controls the global default for the
 265         <varname>AccuracySec=</varname> setting of timer units, see
 266         <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 267         for details. <varname>AccuracySec=</varname> set in individual
 268         units override the global default for the specific unit.
 269         Defaults to 1min. Note that the accuracy of timer units is
 270         also affected by the configured timer slack for PID 1, see
 271         <varname>TimerSlackNSec=</varname> above.</para></listitem>
 272       </varlistentry>
 273
 274       <varlistentry>
 275         <term><varname>DefaultTimeoutStartSec=</varname></term>
 276         <term><varname>DefaultTimeoutStopSec=</varname></term>
 277         <term><varname>DefaultRestartSec=</varname></term>
 278
 279         <listitem><para>Configures the default timeouts for starting
 280         and stopping of units, as well as the default time to sleep
 281         between automatic restarts of units, as configured per-unit in
 282         <varname>TimeoutStartSec=</varname>,
 283         <varname>TimeoutStopSec=</varname> and
 284         <varname>RestartSec=</varname> (for services, see
 285         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 286         for details on the per-unit settings). For non-service units,
 287         <varname>DefaultTimeoutStartSec=</varname> sets the default
 288         <varname>TimeoutSec=</varname>
 289         value. <varname>DefaultTimeoutStartSec=</varname> and
 290         <varname>DefaultTimeoutStopSec=</varname> default to
 291         90s. <varname>DefaultRestartSec=</varname> defaults to
 292         100ms.</para></listitem>
 293       </varlistentry>
 294
 295       <varlistentry>
 296         <term><varname>DefaultStartLimitIntervalSec=</varname></term>
 297         <term><varname>DefaultStartLimitBurst=</varname></term>
 298
 299         <listitem><para>Configure the default unit start rate
 300         limiting, as configured per-service by
 301         <varname>StartLimitIntervalSec=</varname> and
 302         <varname>StartLimitBurst=</varname>. See
 303         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 304         for details on the per-service settings.
 305         <varname>DefaultStartLimitIntervalSec=</varname> defaults to
 306         10s. <varname>DefaultStartLimitBurst=</varname> defaults to
 307         5.</para></listitem>
 308       </varlistentry>
 309
 310       <varlistentry>
 311         <term><varname>DefaultEnvironment=</varname></term>
 312
 313         <listitem><para>Sets manager environment variables passed to
 314         all executed processes. Takes a space-separated list of
 315         variable assignments. See
 316         <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 317         for details about environment variables.</para>
 318
 319         <para>Example:
 320
 321         <programlisting>DefaultEnvironment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</programlisting>
 322
 323         Sets three variables
 324         <literal>VAR1</literal>,
 325         <literal>VAR2</literal>,
 326         <literal>VAR3</literal>.</para></listitem>
 327       </varlistentry>
 328
 329       <varlistentry>
 330         <term><varname>DefaultCPUAccounting=</varname></term>
 331         <term><varname>DefaultBlockIOAccounting=</varname></term>
 332         <term><varname>DefaultMemoryAccounting=</varname></term>
 333         <term><varname>DefaultTasksAccounting=</varname></term>
 334         <term><varname>DefaultIPAccounting=</varname></term>
 335
 336         <listitem><para>Configure the default resource accounting settings, as configured per-unit by
 337         <varname>CPUAccounting=</varname>, <varname>BlockIOAccounting=</varname>, <varname>MemoryAccounting=</varname>,
 338         <varname>TasksAccounting=</varname> and <varname>IPAccounting=</varname>. See
 339         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 340         for details on the per-unit settings. <varname>DefaultTasksAccounting=</varname> defaults to on,
 341         <varname>DefaultMemoryAccounting=</varname> to &MEMORY_ACCOUNTING_DEFAULT;,
 342         the other three settings to off.</para></listitem>
 343       </varlistentry>
 344
 345       <varlistentry>
 346         <term><varname>DefaultTasksMax=</varname></term>
 347
 348         <listitem><para>Configure the default value for the per-unit <varname>TasksMax=</varname> setting. See
 349         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 350         for details. This setting applies to all unit types that support resource control settings, with the exception
 351         of slice units. Defaults to 15%, which equals 4915 with the kernel's defaults on the host, but might be smaller
 352         in OS containers.</para></listitem>
 353       </varlistentry>
 354
 355       <varlistentry>
 356         <term><varname>DefaultLimitCPU=</varname></term>
 357         <term><varname>DefaultLimitFSIZE=</varname></term>
 358         <term><varname>DefaultLimitDATA=</varname></term>
 359         <term><varname>DefaultLimitSTACK=</varname></term>
 360         <term><varname>DefaultLimitCORE=</varname></term>
 361         <term><varname>DefaultLimitRSS=</varname></term>
 362         <term><varname>DefaultLimitNOFILE=</varname></term>
 363         <term><varname>DefaultLimitAS=</varname></term>
 364         <term><varname>DefaultLimitNPROC=</varname></term>
 365         <term><varname>DefaultLimitMEMLOCK=</varname></term>
 366         <term><varname>DefaultLimitLOCKS=</varname></term>
 367         <term><varname>DefaultLimitSIGPENDING=</varname></term>
 368         <term><varname>DefaultLimitMSGQUEUE=</varname></term>
 369         <term><varname>DefaultLimitNICE=</varname></term>
 370         <term><varname>DefaultLimitRTPRIO=</varname></term>
 371         <term><varname>DefaultLimitRTTIME=</varname></term>
 372
 373         <listitem><para>These settings control various default
 374         resource limits for units. See
 375         <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 376         for details. The resource limit is possible to specify in two formats,
 377         <option>value</option> to set soft and hard limits to the same value,
 378         or <option>soft:hard</option> to set both limits individually (e.g. DefaultLimitAS=4G:16G).
 379         Use the string <varname>infinity</varname> to
 380         configure no limit on a specific resource. The multiplicative
 381         suffixes K (=1024), M (=1024*1024) and so on for G, T, P and E
 382         may be used for resource limits measured in bytes
 383         (e.g. DefaultLimitAS=16G). For the limits referring to time values,
 384         the usual time units ms, s, min, h and so on may be used (see
 385         <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 386         for details). Note that if no time unit is specified for
 387         <varname>DefaultLimitCPU=</varname> the default unit of seconds is
 388         implied, while for <varname>DefaultLimitRTTIME=</varname> the default
 389         unit of microseconds is implied. Also, note that the effective
 390         granularity of the limits might influence their
 391         enforcement. For example, time limits specified for
 392         <varname>DefaultLimitCPU=</varname> will be rounded up implicitly to
 393         multiples of 1s. These  settings may be overridden in individual units
 394         using the corresponding LimitXXX= directives. Note that these resource
 395         limits are only defaults for units, they are not applied to PID 1
 396         itself.</para></listitem>
 397       </varlistentry>
 398     </variablelist>
 399   </refsect1>
 400
 401   <refsect1>
 402       <title>See Also</title>
 403       <para>
 404         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 405         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 406         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 407         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 408         <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 409         <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 410       </para>
 411   </refsect1>
 412
 413 </refentry>