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| <refentry id="systemd" |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>systemd</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>systemd</refentrytitle> |
| <manvolnum>1</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>systemd</refname> |
| <refname>init</refname> |
| <refpurpose>systemd system and service manager</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <cmdsynopsis> |
| <command>/usr/lib/systemd/systemd</command> |
| <arg choice="opt" rep="repeat">OPTIONS</arg> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>init</command> |
| <arg choice="opt" rep="repeat">OPTIONS</arg> |
| <arg choice="req">COMMAND</arg> |
| </cmdsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para>systemd is a system and service manager for Linux operating |
| systems. When run as first process on boot (as PID 1), it acts as |
| init system that brings up and maintains userspace |
| services.</para> |
| |
| <para>For compatibility with SysV, if systemd is called as |
| <command>init</command> and a PID that is not 1, it will execute |
| <command>telinit</command> and pass all command line arguments |
| unmodified. That means <command>init</command> and |
| <command>telinit</command> are mostly equivalent when invoked from |
| normal login sessions. See |
| <citerefentry><refentrytitle>telinit</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for more information.</para> |
| |
| <para>When run as a system instance, systemd interprets the |
| configuration file <filename>system.conf</filename> and the files |
| in <filename>system.conf.d</filename> directories; when run as a |
| user instance, systemd interprets the configuration file |
| <filename>user.conf</filename> and the files in |
| <filename>user.conf.d</filename> directories. See |
| <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| for more information.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Options</title> |
| |
| <para>The following options are understood:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>--test</option></term> |
| |
| <listitem><para>Determine startup sequence, dump it and exit. |
| This is an option useful for debugging only.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--dump-configuration-items</option></term> |
| |
| <listitem><para>Dump understood unit configuration items. This |
| outputs a terse but complete list of configuration items |
| understood in unit definition files.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--dump-bus-properties</option></term> |
| |
| <listitem><para>Dump exposed bus properties. This outputs |
| a terse but complete list of properties exposed to dbus. |
| </para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--unit=</option></term> |
| |
| <listitem><para>Set default unit to activate on startup. If |
| not specified, defaults to |
| <filename>default.target</filename>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--system</option></term> |
| <term><option>--user</option></term> |
| |
| <listitem><para>For <option>--system</option>, tell systemd to |
| run a system instance, even if the process ID is not 1, i.e. |
| systemd is not run as init process. <option>--user</option> |
| does the opposite, running a user instance even if the process |
| ID is 1. Normally, it should not be necessary to pass these |
| options, as systemd automatically detects the mode it is |
| started in. These options are hence of little use except for |
| debugging. Note that it is not supported booting and |
| maintaining a full system with systemd running in |
| <option>--system</option> mode, but PID not 1. In practice, |
| passing <option>--system</option> explicitly is only useful in |
| conjunction with <option>--test</option>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--dump-core</option></term> |
| |
| <listitem><para>Enable core dumping on crash. This switch has |
| no effect when running as user instance. This setting may also |
| be enabled during boot on the kernel command line via the |
| <varname>systemd.dump_core=</varname> option, see |
| below.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--crash-vt=</option><replaceable>VT</replaceable></term> |
| |
| <listitem><para>Switch to a specific virtual console (VT) on |
| crash. Takes a positive integer in the range 1–63, or a |
| boolean argument. If an integer is passed, selects which VT to |
| switch to. If <constant>yes</constant>, the VT kernel messages |
| are written to is selected. If <constant>no</constant>, no VT |
| switch is attempted. This switch has no effect when running as |
| user instance. This setting may also be enabled during boot, |
| on the kernel command line via the |
| <varname>systemd.crash_vt=</varname> option, see |
| <!-- FIXME: there is no crash_vt command line option? --> |
| below.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--crash-shell</option></term> |
| |
| <listitem><para>Run a shell on crash. This switch has no |
| effect when running as user instance. This setting may also be |
| enabled during boot, on the kernel command line via the |
| <varname>systemd.crash_shell=</varname> option, see |
| below.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--crash-reboot</option></term> |
| |
| <listitem><para>Automatically reboot the system on crash. This |
| switch has no effect when running as user instance. This |
| setting may also be enabled during boot, on the kernel command |
| line via the <varname>systemd.crash_reboot=</varname> option, |
| see below.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--confirm-spawn</option></term> |
| |
| <listitem><para>Ask for confirmation when spawning processes. |
| This switch has no effect when run as user |
| instance.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--show-status=</option></term> |
| |
| <listitem><para>Takes a boolean argument or the special value <constant>auto</constant>. If on, terse unit |
| status information is shown on the console during boot-up and shutdown. If off, no such status information is |
| shown. If set to <constant>auto</constant> behavior is similar to off, except that it is automatically switched |
| to on, as soon as the first unit failure or significant boot delay is encountered. This switch has no effect |
| when invoked as user instance. If specified, overrides both the kernel command line setting |
| <varname>systemd.show_status=</varname> (see below) and the configuration file option |
| <option>ShowStatus=</option>, see |
| <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--log-target=</option></term> |
| |
| <listitem><para>Set log target. Argument must be one of |
| <option>console</option>, |
| <option>journal</option>, |
| <option>kmsg</option>, |
| <option>journal-or-kmsg</option>, |
| <option>null</option>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--log-level=</option></term> |
| |
| <listitem><para>Set log level. As |
| argument this accepts a numerical log |
| level or the well-known <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| symbolic names (lowercase): |
| <option>emerg</option>, |
| <option>alert</option>, |
| <option>crit</option>, |
| <option>err</option>, |
| <option>warning</option>, |
| <option>notice</option>, |
| <option>info</option>, |
| <option>debug</option>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--log-color=</option></term> |
| |
| <listitem><para>Highlight important log messages. Argument is |
| a boolean value. If the argument is omitted, it defaults to |
| <option>true</option>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--log-location=</option></term> |
| |
| <listitem><para>Include code location in log messages. This is |
| mostly relevant for debugging purposes. Argument is a boolean |
| value. If the argument is omitted it defaults to |
| <option>true</option>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--default-standard-output=</option></term> |
| <term><option>--default-standard-error=</option></term> |
| |
| <listitem><para>Sets the default output or error output for |
| all services and sockets, respectively. That is, controls the |
| default for <option>StandardOutput=</option> and |
| <option>StandardError=</option> (see |
| <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| for details). Takes one of |
| <option>inherit</option>, |
| <option>null</option>, |
| <option>tty</option>, |
| <option>journal</option>, |
| <option>journal+console</option>, |
| <option>syslog</option>, |
| <option>syslog+console</option>, |
| <option>kmsg</option>, |
| <option>kmsg+console</option>. If the |
| argument is omitted |
| <option>--default-standard-output=</option> defaults to |
| <option>journal</option> and |
| <option>--default-standard-error=</option> to |
| <option>inherit</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--machine-id=</option></term> |
| |
| <listitem><para>Override the machine-id set on the hard drive, |
| useful for network booting or for containers. May not be set |
| to all zeros.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--service-watchdogs=</option></term> |
| |
| <listitem><para>Globally enable/disable all service watchdog timeouts and emergency |
| actions. This setting may also be specified during boot, on the kernel |
| command line via the <varname>systemd.service_watchdogs=</varname> |
| option, see below. Defaults to enabled.</para></listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| <xi:include href="standard-options.xml" xpointer="version" /> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Concepts</title> |
| |
| <para>systemd provides a dependency system between various |
| entities called "units" of 11 different types. Units encapsulate |
| various objects that are relevant for system boot-up and |
| maintenance. The majority of units are configured in unit |
| configuration files, whose syntax and basic set of options is |
| described in |
| <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| however some are created automatically from other configuration, |
| dynamically from system state or programmatically at runtime. |
| Units may be "active" (meaning started, bound, plugged in, …, |
| depending on the unit type, see below), or "inactive" (meaning |
| stopped, unbound, unplugged, …), as well as in the process of |
| being activated or deactivated, i.e. between the two states (these |
| states are called "activating", "deactivating"). A special |
| "failed" state is available as well, which is very similar to |
| "inactive" and is entered when the service failed in some way |
| (process returned error code on exit, or crashed, an operation |
| timed out, or after too many restarts). If this state is entered, |
| the cause will be logged, for later reference. Note that the |
| various unit types may have a number of additional substates, |
| which are mapped to the five generalized unit states described |
| here.</para> |
| |
| <para>The following unit types are available:</para> |
| |
| <orderedlist> |
| <listitem><para>Service units, which start and control daemons |
| and the processes they consist of. For details, see |
| <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Socket units, which encapsulate local IPC or |
| network sockets in the system, useful for socket-based |
| activation. For details about socket units, see |
| <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| for details on socket-based activation and other forms of |
| activation, see |
| <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Target units are useful to group units, or |
| provide well-known synchronization points during boot-up, see |
| <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Device units expose kernel devices in systemd |
| and may be used to implement device-based activation. For |
| details, see |
| <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Mount units control mount points in the file |
| system, for details see |
| <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Automount units provide automount capabilities, |
| for on-demand mounting of file systems as well as parallelized |
| boot-up. See |
| <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Timer units are useful for triggering activation |
| of other units based on timers. You may find details in |
| <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Swap units are very similar to mount units and |
| encapsulate memory swap partitions or files of the operating |
| system. They are described in |
| <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Path units may be used to activate other |
| services when file system objects change or are modified. See |
| <citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Slice units may be used to group units which |
| manage system processes (such as service and scope units) in a |
| hierarchical tree for resource management purposes. See |
| <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| <listitem><para>Scope units are similar to service units, but |
| manage foreign processes instead of starting them as well. See |
| <citerefentry><refentrytitle>systemd.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem> |
| |
| </orderedlist> |
| |
| <para>Units are named as their configuration files. Some units |
| have special semantics. A detailed list is available in |
| <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
| |
| <para>systemd knows various kinds of dependencies, including |
| positive and negative requirement dependencies (i.e. |
| <varname>Requires=</varname> and <varname>Conflicts=</varname>) as |
| well as ordering dependencies (<varname>After=</varname> and |
| <varname>Before=</varname>). NB: ordering and requirement |
| dependencies are orthogonal. If only a requirement dependency |
| exists between two units (e.g. <filename>foo.service</filename> |
| requires <filename>bar.service</filename>), but no ordering |
| dependency (e.g. <filename>foo.service</filename> after |
| <filename>bar.service</filename>) and both are requested to start, |
| they will be started in parallel. It is a common pattern that both |
| requirement and ordering dependencies are placed between two |
| units. Also note that the majority of dependencies are implicitly |
| created and maintained by systemd. In most cases, it should be |
| unnecessary to declare additional dependencies manually, however |
| it is possible to do this.</para> |
| |
| <para>Application programs and units (via dependencies) may |
| request state changes of units. In systemd, these requests are |
| encapsulated as 'jobs' and maintained in a job queue. Jobs may |
| succeed or can fail, their execution is ordered based on the |
| ordering dependencies of the units they have been scheduled |
| for.</para> |
| |
| <para>On boot systemd activates the target unit |
| <filename>default.target</filename> whose job is to activate |
| on-boot services and other on-boot units by pulling them in via |
| dependencies. Usually, the unit name is just an alias (symlink) for |
| either <filename>graphical.target</filename> (for fully-featured |
| boots into the UI) or <filename>multi-user.target</filename> (for |
| limited console-only boots for use in embedded or server |
| environments, or similar; a subset of graphical.target). However, |
| it is at the discretion of the administrator to configure it as an |
| alias to any other target unit. See |
| <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for details about these target units.</para> |
| |
| <para>Processes systemd spawns are placed in individual Linux |
| control groups named after the unit which they belong to in the |
| private systemd hierarchy. (see <ulink |
| url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink> |
| for more information about control groups, or short "cgroups"). |
| systemd uses this to effectively keep track of processes. Control |
| group information is maintained in the kernel, and is accessible |
| via the file system hierarchy (beneath |
| <filename>/sys/fs/cgroup/systemd/</filename>), or in tools such as |
| <citerefentry project='man-pages'><refentrytitle>systemd-cgls</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| or |
| <citerefentry project='man-pages'><refentrytitle>ps</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| (<command>ps xawf -eo pid,user,cgroup,args</command> is |
| particularly useful to list all processes and the systemd units |
| they belong to.).</para> |
| |
| <para>systemd is compatible with the SysV init system to a large |
| degree: SysV init scripts are supported and simply read as an |
| alternative (though limited) configuration file format. The SysV |
| <filename>/dev/initctl</filename> interface is provided, and |
| compatibility implementations of the various SysV client tools are |
| available. In addition to that, various established Unix |
| functionality such as <filename>/etc/fstab</filename> or the |
| <filename>utmp</filename> database are supported.</para> |
| |
| <para>systemd has a minimal transaction system: if a unit is |
| requested to start up or shut down it will add it and all its |
| dependencies to a temporary transaction. Then, it will verify if |
| the transaction is consistent (i.e. whether the ordering of all |
| units is cycle-free). If it is not, systemd will try to fix it up, |
| and removes non-essential jobs from the transaction that might |
| remove the loop. Also, systemd tries to suppress non-essential |
| jobs in the transaction that would stop a running service. Finally |
| it is checked whether the jobs of the transaction contradict jobs |
| that have already been queued, and optionally the transaction is |
| aborted then. If all worked out and the transaction is consistent |
| and minimized in its impact it is merged with all already |
| outstanding jobs and added to the run queue. Effectively this |
| means that before executing a requested operation, systemd will |
| verify that it makes sense, fixing it if possible, and only |
| failing if it really cannot work.</para> |
| |
| <para>systemd contains native implementations of various tasks |
| that need to be executed as part of the boot process. For example, |
| it sets the hostname or configures the loopback network device. It |
| also sets up and mounts various API file systems, such as |
| <filename>/sys</filename> or <filename>/proc</filename>.</para> |
| |
| <para>For more information about the concepts and |
| ideas behind systemd, please refer to the |
| <ulink url="http://0pointer.de/blog/projects/systemd.html">Original Design Document</ulink>.</para> |
| |
| <para>Note that some but not all interfaces provided |
| by systemd are covered by the |
| <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface |
| Stability Promise</ulink>.</para> |
| |
| <para>Units may be generated dynamically at boot and system |
| manager reload time, for example based on other configuration |
| files or parameters passed on the kernel command line. For details, see |
| <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
| |
| <para>Systems which invoke systemd in a container or initrd |
| environment should implement the |
| <ulink url="https://www.freedesktop.org/wiki/Software/systemd/ContainerInterface">Container Interface</ulink> or |
| <ulink url="https://www.freedesktop.org/wiki/Software/systemd/InitrdInterface">initrd Interface</ulink> |
| specifications, respectively.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Directories</title> |
| |
| <variablelist> |
| <varlistentry> |
| <term>System unit directories</term> |
| |
| <listitem><para>The systemd system manager reads unit |
| configuration from various directories. Packages that want to |
| install unit files shall place them in the directory returned |
| by <command>pkg-config systemd |
| --variable=systemdsystemunitdir</command>. Other directories |
| checked are <filename>/usr/local/lib/systemd/system</filename> |
| and <filename>/usr/lib/systemd/system</filename>. User |
| configuration always takes precedence. <command>pkg-config |
| systemd --variable=systemdsystemconfdir</command> returns the |
| path of the system configuration directory. Packages should |
| alter the content of these directories only with the |
| <command>enable</command> and <command>disable</command> |
| commands of the |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| tool. Full list of directories is provided in |
| <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
| </para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <variablelist> |
| <varlistentry> |
| <term>User unit directories</term> |
| |
| <listitem><para>Similar rules apply for the user unit |
| directories. However, here the |
| <ulink url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG |
| Base Directory specification</ulink> is followed to find |
| units. Applications should place their unit files in the |
| directory returned by <command>pkg-config systemd |
| --variable=systemduserunitdir</command>. Global configuration |
| is done in the directory reported by <command>pkg-config |
| systemd --variable=systemduserconfdir</command>. The |
| <command>enable</command> and <command>disable</command> |
| commands of the |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| tool can handle both global (i.e. for all users) and private |
| (for one user) enabling/disabling of units. Full list of |
| directories is provided in |
| <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
| </para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <variablelist> |
| <varlistentry> |
| <term>SysV init scripts directory</term> |
| |
| <listitem><para>The location of the SysV init script directory |
| varies between distributions. If systemd cannot find a native |
| unit file for a requested service, it will look for a SysV |
| init script of the same name (with the |
| <filename>.service</filename> suffix |
| removed).</para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <variablelist> |
| <varlistentry> |
| <term>SysV runlevel link farm directory</term> |
| |
| <listitem><para>The location of the SysV runlevel link farm |
| directory varies between distributions. systemd will take the |
| link farm into account when figuring out whether a service |
| shall be enabled. Note that a service unit with a native unit |
| configuration file cannot be started by activating it in the |
| SysV runlevel link farm.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Signals</title> |
| |
| <variablelist> |
| <varlistentry> |
| <term><constant>SIGTERM</constant></term> |
| |
| <listitem><para>Upon receiving this signal the systemd system |
| manager serializes its state, reexecutes itself and |
| deserializes the saved state again. This is mostly equivalent |
| to <command>systemctl daemon-reexec</command>.</para> |
| |
| <para>systemd user managers will start the |
| <filename>exit.target</filename> unit when this signal is |
| received. This is mostly equivalent to <command>systemctl |
| --user start exit.target |
| --job-mode=replace-irreversible</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGINT</constant></term> |
| |
| <listitem><para>Upon receiving this signal the systemd system |
| manager will start the |
| <filename>ctrl-alt-del.target</filename> unit. This is mostly |
| equivalent to <command>systemctl start ctrl-alt-del.target |
| --job-mode=replace-irreversible</command>. If this signal is |
| received more than 7 times per 2s, an immediate reboot is |
| triggered. Note that pressing Ctrl-Alt-Del on the console |
| will trigger this signal. Hence, if a reboot is hanging, |
| pressing Ctrl-Alt-Del more than 7 times in 2s is a relatively |
| safe way to trigger an immediate reboot.</para> |
| |
| <para>systemd user managers treat this signal the same way as |
| <constant>SIGTERM</constant>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGWINCH</constant></term> |
| |
| <listitem><para>When this signal is received the systemd |
| system manager will start the |
| <filename>kbrequest.target</filename> unit. This is mostly |
| equivalent to <command>systemctl start |
| kbrequest.target</command>.</para> |
| |
| <para>This signal is ignored by systemd user |
| managers.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGPWR</constant></term> |
| |
| <listitem><para>When this signal is received the systemd |
| manager will start the <filename>sigpwr.target</filename> |
| unit. This is mostly equivalent to <command>systemctl start |
| sigpwr.target</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGUSR1</constant></term> |
| |
| <listitem><para>When this signal is received the systemd |
| manager will try to reconnect to the D-Bus |
| bus.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGUSR2</constant></term> |
| |
| <listitem><para>When this signal is received the systemd |
| manager will log its complete state in human-readable form. |
| The data logged is the same as printed by |
| <command>systemd-analyze dump</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGHUP</constant></term> |
| |
| <listitem><para>Reloads the complete daemon configuration. |
| This is mostly equivalent to <command>systemctl |
| daemon-reload</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+0</constant></term> |
| |
| <listitem><para>Enters default mode, starts the |
| <filename>default.target</filename> unit. This is mostly |
| equivalent to <command>systemctl isolate |
| default.target</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+1</constant></term> |
| |
| <listitem><para>Enters rescue mode, starts the |
| <filename>rescue.target</filename> unit. This is mostly |
| equivalent to <command>systemctl isolate |
| rescue.target</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+2</constant></term> |
| |
| <listitem><para>Enters emergency mode, starts the |
| <filename>emergency.service</filename> unit. This is mostly |
| equivalent to <command>systemctl isolate |
| emergency.service</command>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+3</constant></term> |
| |
| <listitem><para>Halts the machine, starts the |
| <filename>halt.target</filename> unit. This is mostly |
| equivalent to <command>systemctl start halt.target |
| --job-mode=replace-irreversible</command>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+4</constant></term> |
| |
| <listitem><para>Powers off the machine, starts the |
| <filename>poweroff.target</filename> unit. This is mostly |
| equivalent to <command>systemctl start poweroff.target |
| --job-mode=replace-irreversible</command>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+5</constant></term> |
| |
| <listitem><para>Reboots the machine, starts the |
| <filename>reboot.target</filename> unit. This is mostly |
| equivalent to <command>systemctl start reboot.target |
| --job-mode=replace-irreversible</command>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+6</constant></term> |
| |
| <listitem><para>Reboots the machine via kexec, starts the |
| <filename>kexec.target</filename> unit. This is mostly |
| equivalent to <command>systemctl start kexec.target |
| --job-mode=replace-irreversible</command>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+13</constant></term> |
| |
| <listitem><para>Immediately halts the machine.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+14</constant></term> |
| |
| <listitem><para>Immediately powers off the machine.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+15</constant></term> |
| |
| <listitem><para>Immediately reboots the machine.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+16</constant></term> |
| |
| <listitem><para>Immediately reboots the machine with kexec.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+20</constant></term> |
| |
| <listitem><para>Enables display of status messages on the |
| console, as controlled via |
| <varname>systemd.show_status=1</varname> on the kernel command |
| line.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+21</constant></term> |
| |
| <listitem><para>Disables display of |
| status messages on the console, as |
| controlled via |
| <varname>systemd.show_status=0</varname> |
| on the kernel command |
| line.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+22</constant></term> |
| |
| <listitem><para>Sets the service manager's log level to <literal>debug</literal>, in a fashion equivalent to |
| <varname>systemd.log_level=debug</varname> on the kernel command line.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+23</constant></term> |
| |
| <listitem><para>Restores the log level to its configured value. The configured value is derived from – in order |
| of priority – the value specified with <varname>systemd.log-level=</varname> on the kernel command line, or the |
| value specified with <option>LogLevel=</option> in the configuration file, or the built-in default of |
| <literal>info</literal>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+24</constant></term> |
| |
| <listitem><para>Immediately exits the manager (only available |
| for --user instances).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+26</constant></term> |
| |
| <listitem><para>Restores the log target to its configured value. The configured value is derived from – in |
| order of priority – the value specified with <varname>systemd.log-target=</varname> on the kernel command line, |
| or the value specified with <option>LogTarget=</option> in the configuration file, or the built-in |
| default.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>SIGRTMIN+27</constant></term> |
| <term><constant>SIGRTMIN+28</constant></term> |
| |
| <listitem><para>Sets the log target to <literal>console</literal> on <constant>SIGRTMIN+27</constant> (or |
| <literal>kmsg</literal> on <constant>SIGRTMIN+28</constant>), in a fashion equivalent to |
| <varname>systemd.log_target=console</varname> (or <varname>systemd.log_target=kmsg</varname> on |
| <constant>SIGRTMIN+28</constant>) on the kernel command line.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Environment</title> |
| |
| <variablelist class='environment-variables'> |
| <varlistentry> |
| <term><varname>$SYSTEMD_LOG_LEVEL</varname></term> |
| <listitem><para>systemd reads the log level from this |
| environment variable. This can be overridden with |
| <option>--log-level=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_LOG_TARGET</varname></term> |
| <listitem><para>systemd reads the log target from this |
| environment variable. This can be overridden with |
| <option>--log-target=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_LOG_COLOR</varname></term> |
| <listitem><para>Controls whether systemd highlights important |
| log messages. This can be overridden with |
| <option>--log-color=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_LOG_LOCATION</varname></term> |
| <listitem><para>Controls whether systemd prints the code |
| location along with log messages. This can be overridden with |
| <option>--log-location=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$XDG_CONFIG_HOME</varname></term> |
| <term><varname>$XDG_CONFIG_DIRS</varname></term> |
| <term><varname>$XDG_DATA_HOME</varname></term> |
| <term><varname>$XDG_DATA_DIRS</varname></term> |
| |
| <listitem><para>The systemd user manager uses these variables |
| in accordance to the <ulink |
| url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG |
| Base Directory specification</ulink> to find its |
| configuration.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_UNIT_PATH</varname></term> |
| |
| <listitem><para>Controls where systemd looks for unit |
| files.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_SYSVINIT_PATH</varname></term> |
| |
| <listitem><para>Controls where systemd looks for SysV init |
| scripts.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_SYSVRCND_PATH</varname></term> |
| |
| <listitem><para>Controls where systemd looks for SysV init |
| script runlevel link farms.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_COLORS</varname></term> |
| |
| <listitem><para>The value must be a boolean. Controls whether colorized output should be |
| generated. This can be specified to override the decision that <command>systemd</command> |
| makes based on <varname>$TERM</varname> and what the console is connected to.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$SYSTEMD_URLIFY</varname></term> |
| |
| <listitem><para>The value must be a boolean. Controls whether clickable links should be generated in the output |
| for terminal emulators supporting this. This can be specified to override the decision that |
| <command>systemd</command> makes based on <varname>$TERM</varname> and other conditions.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$LISTEN_PID</varname></term> |
| <term><varname>$LISTEN_FDS</varname></term> |
| <term><varname>$LISTEN_FDNAMES</varname></term> |
| |
| <listitem><para>Set by systemd for supervised processes during |
| socket-based activation. See |
| <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| for more information.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>$NOTIFY_SOCKET</varname></term> |
| |
| <listitem><para>Set by systemd for supervised processes for |
| status and start-up completion notification. See |
| <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| for more information.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Kernel Command Line</title> |
| |
| <para>When run as system instance systemd parses a number of |
| kernel command line arguments<footnote><para>If run inside a Linux |
| container these arguments may be passed as command line arguments |
| to systemd itself, next to any of the command line options listed |
| in the Options section above. If run outside of Linux containers, |
| these arguments are parsed from <filename>/proc/cmdline</filename> |
| instead.</para></footnote>:</para> |
| |
| <variablelist class='kernel-commandline-options'> |
| <varlistentry> |
| <term><varname>systemd.unit=</varname></term> |
| <term><varname>rd.systemd.unit=</varname></term> |
| |
| <listitem><para>Overrides the unit to activate on boot. |
| Defaults to <filename>default.target</filename>. This may be |
| used to temporarily boot into a different boot unit, for |
| example <filename>rescue.target</filename> or |
| <filename>emergency.service</filename>. See |
| <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for details about these units. The option prefixed with |
| <literal>rd.</literal> is honored only in the initial RAM disk |
| (initrd), while the one that is not prefixed only in the main |
| system.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.dump_core</varname></term> |
| |
| <listitem><para>Takes a boolean argument or enables the option if specified |
| without an argument. If enabled, the systemd manager (PID 1) dumps core when |
| it crashes. Otherwise, no core dump is created. Defaults to enabled.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.crash_chvt</varname></term> |
| |
| <listitem><para>Takes a positive integer, or a boolean argument. Can be also |
| specified without an argument, with the same effect as a positive boolean. If |
| a positive integer (in the range 1–63) is specified, the system manager (PID |
| 1) will activate the specified virtual terminal (VT) when it |
| crashes. Defaults to disabled, meaning that no such switch is attempted. If |
| set to enabled, the VT the kernel messages are written to is selected. |
| </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.crash_shell</varname></term> |
| |
| <listitem><para>Takes a boolean argument or enables the option if specified |
| without an argument. If enabled, the system manager (PID 1) spawns a shell |
| when it crashes, after a 10s delay. Otherwise, no shell is spawned. Defaults |
| to disabled, for security reasons, as the shell is not protected by password |
| authentication.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.crash_reboot</varname></term> |
| |
| <listitem><para>Takes a boolean argument or enables the option if specified |
| without an argument. If enabled, the system manager (PID 1) will reboot the |
| machine automatically when it crashes, after a 10s delay. Otherwise, the |
| system will hang indefinitely. Defaults to disabled, in order to avoid a |
| reboot loop. If combined with <varname>systemd.crash_shell</varname>, the |
| system is rebooted after the shell exits.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.confirm_spawn</varname></term> |
| |
| <listitem><para>Takes a boolean argument or a path to the virtual console |
| where the confirmation messages should be emitted. Can be also specified |
| without an argument, with the same effect as a positive boolean. If enabled, |
| the system manager (PID 1) asks for confirmation when spawning processes |
| using <option>/dev/console</option>. If a path or a console name (such as |
| <literal>ttyS0</literal>) is provided, the virtual console pointed to by this |
| path or described by the give name will be used instead. Defaults to disabled. |
| </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.service_watchdogs=</varname></term> |
| |
| <listitem><para>Takes a boolean argument. If disabled, all service runtime |
| watchdogs (<option>WatchdogSec=</option>) and emergency actions (e.g. |
| <option>OnFailure=</option> or <option>StartLimitAction=</option>) are |
| ignored by the system manager (PID 1); see |
| <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
| Defaults to enabled, i.e. watchdogs and failure actions are processed |
| normally. The hardware watchdog is not affected by this |
| option.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.show_status</varname></term> |
| |
| <listitem><para>Takes a boolean argument or the constant |
| <constant>auto</constant>. Can be also specified without an argument, with |
| the same effect as a positive boolean. If enabled, the systemd manager (PID |
| 1) shows terse service status updates on the console during bootup. |
| <constant>auto</constant> behaves like <option>false</option> until a unit |
| fails or there is a significant delay in boot. Defaults to enabled, unless |
| <option>quiet</option> is passed as kernel command line option, in which case |
| it defaults to <constant>auto</constant>. If specified overrides the system |
| manager configuration file option <option>ShowStatus=</option>, see |
| <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
| However, the process command line option <option>--show-status=</option> |
| takes precedence over both this kernel command line option and the |
| configuration file option.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.log_target=</varname></term> |
| <term><varname>systemd.log_level=</varname></term> |
| <term><varname>systemd.log_location=</varname></term> |
| <term><varname>systemd.log_color</varname></term> |
| |
| <listitem><para>Controls log output, with the same effect as the |
| <varname>$SYSTEMD_LOG_TARGET</varname>, |
| <varname>$SYSTEMD_LOG_LEVEL</varname>, |
| <varname>$SYSTEMD_LOG_LOCATION</varname>, |
| <varname>$SYSTEMD_LOG_COLOR</varname> environment variables described above. |
| <varname>systemd.log_color</varname> can be specified without an argument, |
| with the same effect as a positive boolean.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.default_standard_output=</varname></term> |
| <term><varname>systemd.default_standard_error=</varname></term> |
| <listitem><para>Controls default standard output and error |
| output for services, with the same effect as the |
| <option>--default-standard-output=</option> and |
| <option>--default-standard-error=</option> command line |
| arguments described above, respectively.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.setenv=</varname></term> |
| |
| <listitem><para>Takes a string argument in the form |
| VARIABLE=VALUE. May be used to set default environment |
| variables to add to forked child processes. May be used more |
| than once to set multiple variables.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.machine_id=</varname></term> |
| |
| <listitem><para>Takes a 32 character hex value to be |
| used for setting the machine-id. Intended mostly for |
| network booting where the same machine-id is desired |
| for every boot.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.unified_cgroup_hierarchy</varname></term> |
| |
| <listitem><para>When specified without an argument or with a true argument, |
| enables the usage of |
| <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">unified cgroup hierarchy</ulink> |
| (a.k.a. cgroups-v2). When specified with a false argument, fall back to |
| hybrid or full legacy cgroup hierarchy.</para> |
| |
| <para>If this option is not specified, the default behaviour is determined |
| during compilation (the <option>--with-default-hierarchy=</option> |
| option). If the kernel does not support unified cgroup hierarchy, the legacy |
| hierarchy will be used even if this option is specified.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>systemd.legacy_systemd_cgroup_controller</varname></term> |
| |
| <listitem><para>Takes effect if the full unified cgroup hierarchy is not used |
| (see previous option). When specified without an argument or with a true |
| argument, disables the use of "hybrid" cgroup hierarchy (i.e. a cgroups-v2 |
| tree used for systemd, and |
| <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/">legacy |
| cgroup hierarchy</ulink>, a.k.a. cgroups-v1, for other controllers), and |
| forces a full "legacy" mode. When specified with a false argument, enables |
| the use of "hybrid" hierarchy.</para> |
| |
| <para>If this option is not specified, the default behaviour is determined |
| during compilation (the <option>--with-default-hierarchy=</option> |
| option). If the kernel does not support unified cgroup hierarchy, the legacy |
| hierarchy will be used even if this option is specified.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>quiet</varname></term> |
| |
| <listitem><para>Turn off status output at boot, much like |
| <varname>systemd.show_status=false</varname> would. Note that |
| this option is also read by the kernel itself and disables |
| kernel log output. Passing this option hence turns off the |
| usual output from both the system manager and the kernel. |
| </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>debug</varname></term> |
| |
| <listitem><para>Turn on debugging output. This is equivalent |
| to <varname>systemd.log_level=debug</varname>. Note that this |
| option is also read by the kernel itself and enables kernel |
| debug output. Passing this option hence turns on the debug |
| output from both the system manager and the |
| kernel.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>emergency</varname></term> |
| <term><varname>rd.emergency</varname></term> |
| <term><varname>-b</varname></term> |
| |
| <listitem><para>Boot into emergency mode. This is equivalent |
| to <varname>systemd.unit=emergency.target</varname> or |
| <varname>rd.systemd.unit=emergency.target</varname>, respectively, and |
| provided for compatibility reasons and to be easier to type.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>rescue</varname></term> |
| <term><varname>rd.rescue</varname></term> |
| <term><varname>single</varname></term> |
| <term><varname>s</varname></term> |
| <term><varname>S</varname></term> |
| <term><varname>1</varname></term> |
| |
| <listitem><para>Boot into rescue mode. This is equivalent to |
| <varname>systemd.unit=rescue.target</varname> or |
| <varname>rd.systemd.unit=rescue.target</varname>, respectively, and |
| provided for compatibility reasons and to be easier to type.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>2</varname></term> |
| <term><varname>3</varname></term> |
| <term><varname>4</varname></term> |
| <term><varname>5</varname></term> |
| |
| <listitem><para>Boot into the specified legacy SysV runlevel. |
| These are equivalent to |
| <varname>systemd.unit=runlevel2.target</varname>, |
| <varname>systemd.unit=runlevel3.target</varname>, |
| <varname>systemd.unit=runlevel4.target</varname>, and |
| <varname>systemd.unit=runlevel5.target</varname>, |
| respectively, and provided for compatibility reasons and to be |
| easier to type.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>locale.LANG=</varname></term> |
| <term><varname>locale.LANGUAGE=</varname></term> |
| <term><varname>locale.LC_CTYPE=</varname></term> |
| <term><varname>locale.LC_NUMERIC=</varname></term> |
| <term><varname>locale.LC_TIME=</varname></term> |
| <term><varname>locale.LC_COLLATE=</varname></term> |
| <term><varname>locale.LC_MONETARY=</varname></term> |
| <term><varname>locale.LC_MESSAGES=</varname></term> |
| <term><varname>locale.LC_PAPER=</varname></term> |
| <term><varname>locale.LC_NAME=</varname></term> |
| <term><varname>locale.LC_ADDRESS=</varname></term> |
| <term><varname>locale.LC_TELEPHONE=</varname></term> |
| <term><varname>locale.LC_MEASUREMENT=</varname></term> |
| <term><varname>locale.LC_IDENTIFICATION=</varname></term> |
| |
| <listitem><para>Set the system locale to use. This overrides |
| the settings in <filename>/etc/locale.conf</filename>. For |
| more information, see |
| <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| and |
| <citerefentry project='man-pages'><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>. |
| </para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <para>For other kernel command line parameters understood by |
| components of the core OS, please refer to |
| <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Sockets and FIFOs</title> |
| |
| <variablelist> |
| <varlistentry> |
| <term><filename>/run/systemd/notify</filename></term> |
| |
| <listitem><para>Daemon status notification socket. This is an |
| <constant>AF_UNIX</constant> datagram socket and is used to |
| implement the daemon notification logic as implemented by |
| <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> |
| |
| </varlistentry> |
| |
| <varlistentry> |
| <term><filename>/run/systemd/private</filename></term> |
| |
| <listitem><para>Used internally as communication channel |
| between |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| and the systemd process. This is an |
| <constant>AF_UNIX</constant> stream socket. This interface is |
| private to systemd and should not be used in external |
| projects.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><filename>/dev/initctl</filename></term> |
| |
| <listitem><para>Limited compatibility support for the SysV |
| client interface, as implemented by the |
| <filename>systemd-initctl.service</filename> unit. This is a |
| named pipe in the file system. This interface is obsolete and |
| should not be used in new applications.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| The <ulink url="https://www.freedesktop.org/wiki/Software/systemd/">systemd Homepage</ulink>, |
| <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-notify</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| <citerefentry project='man-pages'><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |