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954 lines
54 KiB
XML
954 lines
54 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="systemd.unit">
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<refentryinfo>
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<title>systemd.unit</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>systemd.unit</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd.unit</refname>
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<refpurpose>systemd unit configuration files</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename>systemd.service</filename>,
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<filename>systemd.socket</filename>,
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<filename>systemd.device</filename>,
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<filename>systemd.mount</filename>,
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<filename>systemd.automount</filename>,
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<filename>systemd.swap</filename>,
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<filename>systemd.target</filename>,
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<filename>systemd.path</filename>,
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<filename>systemd.timer</filename>,
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<filename>systemd.snapshot</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>A unit configuration file encodes information
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about a service, a socket, a device, a mount point, an
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automount point, a swap file or partition, a start-up
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target, a file system path or a timer controlled and
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supervised by
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>. The
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syntax is inspired by <ulink
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url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG
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Desktop Entry Specification</ulink> <filename>.desktop</filename> files, which are in turn
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inspired by Microsoft Windows
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<filename>.ini</filename> files.</para>
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<para>This man pages lists the common configuration
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options of all the unit types. These options need to
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be configured in the [Unit] resp. [Install]
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section of the unit files.</para>
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<para>In addition to the generic [Unit] and [Install]
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sections described here, each unit should have a
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type-specific section, e.g. [Service] for a service
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unit. See the respective man pages for more
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information.</para>
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<para>Unit files may contain additional options on top
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of those listed here. If systemd encounters an unknown
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option it will write a warning log message but
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continue loading the unit. If an option is prefixed
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with <option>X-</option> it is ignored completely by
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systemd. Applications may use this to include
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additional information in the unit files.</para>
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<para>Boolean arguments used in unit files can be
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written in various formats. For positive settings the
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strings <option>1</option>, <option>yes</option>,
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<option>true</option> and <option>on</option> are
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equivalent. For negative settings the strings
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<option>0</option>, <option>no</option>,
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<option>false</option> and <option>off</option> are
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equivalent.</para>
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<para>Time span values encoded in unit files can be
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written in various formats. A stand-alone number
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specifies a time in seconds. If suffixed with a time
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unit, the unit is honored. A concatenation of
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multiple values with units is supported, in which case
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the values are added up. Example: "50" refers to 50
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seconds; "2min 200ms" refers to 2 minutes plus 200
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milliseconds, i.e. 120200ms. The following time units
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are understood: s, min, h, d, w, ms, us.</para>
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<para>Empty lines and lines starting with # or ; are
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ignored. This may be used for commenting. Lines ending
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in a backslash are concatenated with the following
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line while reading and the backslash is replaced by a
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space character. This may be used to wrap long lines.</para>
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<para>If a line starts with <option>.include</option>
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followed by a file name, the specified file will be
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parsed at this point. Make sure that the file that is
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included has the appropiate section headers before
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any directives.</para>
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<para>Along with a unit file
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<filename>foo.service</filename> a directory
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<filename>foo.service.wants/</filename> may exist. All
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units symlinked from such a directory are implicitly
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added as dependencies of type
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<varname>Wanted=</varname> to the unit. This is useful
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to hook units into the start-up of other units,
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without having to modify their unit configuration
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files. For details about the semantics of
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<varname>Wanted=</varname> see below. The preferred
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way to create symlinks in the
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<filename>.wants/</filename> directory of a service is
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with the <command>enable</command> command of the
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<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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tool which reads information from the [Install]
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section of unit files. (See below.) A similar
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functionality exists for <varname>Requires=</varname>
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type dependencies as well, the directory suffix is
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<filename>.requires/</filename> in this case.</para>
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<para>Note that while systemd offers a flexible
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dependency system between units it is recommended to
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use this functionality only sparsely and instead rely
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on techniques such as bus-based or socket-based
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activation which makes dependencies implicit, which
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both results in a simpler and more flexible
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system.</para>
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<para>Some unit names reflect paths existing in the
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file system name space. Example: a device unit
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<filename>dev-sda.device</filename> refers to a device
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with the device node <filename>/dev/sda</filename> in
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the file system namespace. If this applies a special
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way to escape the path name is used, so that the
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result is usable as part of a file name. Basically,
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given a path, "/" is replaced by "-", and all
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unprintable characters and the "-" are replaced by
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C-style "\x20" escapes. The root directory "/" is
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encoded as single dash, while otherwise the initial
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and ending "/" is removed from all paths during
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transformation. This escaping is reversible.</para>
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<para>Optionally, units may be instantiated from a
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template file at runtime. This allows creation of
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multiple units from a single configuration file. If
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systemd looks for a unit configuration file it will
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first search for the literal unit name in the
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filesystem. If that yields no success and the unit
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name contains an @ character, systemd will look for a
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unit template that shares the same name but with the
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instance string (i.e. the part between the @ character
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and the suffix) removed. Example: if a service
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<filename>getty@tty3.service</filename> is requested
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and no file by that name is found, systemd will look
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for <filename>getty@.service</filename> and
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instantiate a service from that configuration file if
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it is found.</para>
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<para>To refer to the instance string from
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within the configuration file you may use the special
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<literal>%i</literal> specifier in many of the
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configuration options. Other specifiers exist, the
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full list is:</para>
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<table>
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<title>Specifiers available in unit files</title>
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<tgroup cols='3' align='left' colsep='1' rowsep='1'>
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<colspec colname="spec" />
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<colspec colname="mean" />
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<colspec colname="detail" />
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<thead>
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<row>
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<entry>Specifier</entry>
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<entry>Meaning</entry>
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<entry>Details</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><literal>%n</literal></entry>
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<entry>Full unit name</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%N</literal></entry>
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<entry>Unescaped full unit name</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%p</literal></entry>
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<entry>Prefix name</entry>
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<entry>This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name.</entry>
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</row>
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<row>
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<entry><literal>%P</literal></entry>
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<entry>Unescaped prefix name</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%i</literal></entry>
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<entry>Instance name</entry>
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<entry>This is the string between the @ character and the suffix.</entry>
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</row>
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<row>
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<entry><literal>%I</literal></entry>
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<entry>Unescaped instance name</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%f</literal></entry>
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<entry>Unescaped file name</entry>
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<entry>This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.</entry>
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</row>
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<row>
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<entry><literal>%c</literal></entry>
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<entry>Control group path of the unit</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%r</literal></entry>
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<entry>Root control group path of systemd</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%R</literal></entry>
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<entry>Parent directory of the root control group path of systemd</entry>
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<entry></entry>
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</row>
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<row>
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<entry><literal>%t</literal></entry>
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<entry>Runtime socket dir</entry>
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<entry>This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers).</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>If a unit file is empty (i.e. has the file size
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0) or is symlinked to <filename>/dev/null</filename>
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its configuration will not be loaded and it appears
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with a load state of <literal>masked</literal>, and
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cannot be activated. Use this as an effective way to
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fully disable a unit, making it impossible to start it
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even manually.</para>
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<para>The unit file format is covered by the
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<ulink
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url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface
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Stability Promise</ulink>.</para>
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</refsect1>
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<refsect1>
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<title>Options</title>
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<para>Unit file may include a [Unit] section, which
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carries generic information about the unit that is not
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dependent on the type of unit:</para>
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<variablelist>
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<varlistentry>
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<term><varname>Description=</varname></term>
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<listitem><para>A free-form string
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describing the unit. This is intended
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for use in UIs to show descriptive
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information along with the unit
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name.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Requires=</varname></term>
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<listitem><para>Configures requirement
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dependencies on other units. If this
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unit gets activated, the units listed
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here will be activated as well. If one
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of the other units gets deactivated or
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its activation fails, this unit will
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be deactivated. This option may be
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specified more than once, in which
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case requirement dependencies for all
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listed names are created. Note that
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requirement dependencies do not
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influence the order in which services
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are started or stopped. This has to be
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configured independently with the
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<varname>After=</varname> or
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<varname>Before=</varname> options. If
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a unit
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<filename>foo.service</filename>
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requires a unit
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<filename>bar.service</filename> as
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configured with
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<varname>Requires=</varname> and no
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ordering is configured with
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<varname>After=</varname> or
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<varname>Before=</varname>, then both
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units will be started simultaneously
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and without any delay between them if
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<filename>foo.service</filename> is
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activated. Often it is a better choice
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to use <varname>Wants=</varname>
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instead of
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<varname>Requires=</varname> in order
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to achieve a system that is more
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robust when dealing with failing
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services.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>RequiresOverridable=</varname></term>
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<listitem><para>Similar to
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<varname>Requires=</varname>.
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Dependencies listed in
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<varname>RequiresOverridable=</varname>
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which cannot be fulfilled or fail to
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start are ignored if the startup was
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explicitly requested by the user. If
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the start-up was pulled in indirectly
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by some dependency or automatic
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start-up of units that is not
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requested by the user this dependency
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must be fulfilled and otherwise the
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transaction fails. Hence, this option
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may be used to configure dependencies
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that are normally honored unless the
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user explicitly starts up the unit, in
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which case whether they failed or not
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is irrelevant.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Requisite=</varname></term>
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<term><varname>RequisiteOverridable=</varname></term>
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<listitem><para>Similar to
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<varname>Requires=</varname>
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resp. <varname>RequiresOverridable=</varname>. However,
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if a unit listed here is not started
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already it will not be started and the
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transaction fails
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immediately.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Wants=</varname></term>
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<listitem><para>A weaker version of
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<varname>Requires=</varname>. A unit
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listed in this option will be started
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if the configuring unit is. However,
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if the listed unit fails to start up
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or cannot be added to the transaction
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this has no impact on the validity of
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the transaction as a whole. This is
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the recommended way to hook start-up
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of one unit to the start-up of another
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unit. Note that dependencies of this
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type may also be configured outside of
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the unit configuration file by
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adding a symlink to a
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<filename>.wants/</filename> directory
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accompanying the unit file. For
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details see above.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>BindTo=</varname></term>
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<listitem><para>Configures requirement
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dependencies, very similar in style to
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<varname>Requires=</varname>, however
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in addition to this behaviour it also
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declares that this unit is stopped
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when any of the units listed suddenly
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disappears. Units can suddenly,
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unexpectedly disappear if a service
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terminates on its own choice, a device
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is unplugged or a mount point
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|
unmounted without involvement of
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systemd.</para></listitem>
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</varlistentry>
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|
|
<varlistentry>
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<term><varname>Conflicts=</varname></term>
|
|
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|
<listitem><para>Configures negative
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|
requirement dependencies. If a unit
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has a
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<varname>Conflicts=</varname> setting
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|
on another unit, starting the former
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|
will stop the latter and vice
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|
versa. Note that this setting is
|
|
independent of and orthogonal to the
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|
<varname>After=</varname> and
|
|
<varname>Before=</varname> ordering
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|
dependencies.</para>
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<para>If a unit A that conflicts with
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a unit B is scheduled to be started at
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|
the same time as B, the transaction
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|
will either fail (in case both are
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|
required part of the transaction) or
|
|
be modified to be fixed (in case one
|
|
or both jobs are not a required part
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|
of the transaction). In the latter
|
|
case the job that is not the required
|
|
will be removed, or in case both are
|
|
not required the unit that conflicts
|
|
will be started and the unit that is
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|
conflicted is
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|
stopped.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Before=</varname></term>
|
|
<term><varname>After=</varname></term>
|
|
|
|
<listitem><para>Configures ordering
|
|
dependencies between units. If a unit
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|
<filename>foo.service</filename>
|
|
contains a setting
|
|
<option>Before=bar.service</option>
|
|
and both units are being started,
|
|
<filename>bar.service</filename>'s
|
|
start-up is delayed until
|
|
<filename>foo.service</filename> is
|
|
started up. Note that this setting is
|
|
independent of and orthogonal to the
|
|
requirement dependencies as configured
|
|
by <varname>Requires=</varname>. It is
|
|
a common pattern to include a unit
|
|
name in both the
|
|
<varname>After=</varname> and
|
|
<varname>Requires=</varname> option in
|
|
which case the unit listed will be
|
|
started before the unit that is
|
|
configured with these options. This
|
|
option may be specified more than
|
|
once, in which case ordering
|
|
dependencies for all listed names are
|
|
created. <varname>After=</varname> is
|
|
the inverse of
|
|
<varname>Before=</varname>, i.e. while
|
|
<varname>After=</varname> ensures that
|
|
the configured unit is started after
|
|
the listed unit finished starting up,
|
|
<varname>Before=</varname> ensures the
|
|
opposite, i.e. that the configured
|
|
unit is fully started up before the
|
|
listed unit is started. Note that when
|
|
two units with an ordering dependency
|
|
between them are shut down, the
|
|
inverse of the start-up order is
|
|
applied. i.e. if a unit is configured
|
|
with <varname>After=</varname> on
|
|
another unit, the former is stopped
|
|
before the latter if both are shut
|
|
down. If one unit with an ordering
|
|
dependency on another unit is shut
|
|
down while the latter is started up,
|
|
the shut down is ordered before the
|
|
start-up regardless whether the
|
|
ordering dependency is actually of
|
|
type <varname>After=</varname> or
|
|
<varname>Before=</varname>. If two
|
|
units have no ordering dependencies
|
|
between them they are shut down
|
|
resp. started up simultaneously, and
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|
no ordering takes
|
|
place. </para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>OnFailure=</varname></term>
|
|
|
|
<listitem><para>Lists one or more
|
|
units that are activated when this
|
|
unit enters the
|
|
'<literal>failed</literal>'
|
|
state.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>OnFailureIsolate=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option> the
|
|
unit listed in
|
|
<varname>OnFailure=</varname> will be
|
|
enqueued in isolation mode, i.e. all
|
|
units that are not its dependency will
|
|
be stopped. If this is set only a
|
|
single unit may be listed in
|
|
<varname>OnFailure=</varname>. Defaults
|
|
to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IgnoreOnIsolate=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option>
|
|
this unit will not be stopped when
|
|
isolating another unit. Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IgnoreOnSnapshot=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option>
|
|
this unit will not be included in
|
|
snapshots. Defaults to
|
|
<option>true</option> for device and
|
|
snapshot units, <option>false</option>
|
|
for the others.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>StopWhenUnneeded=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option>
|
|
this unit will be stopped when it is
|
|
no longer used. Note that in order to
|
|
minimize the work to be executed,
|
|
systemd will not stop units by default
|
|
unless they are conflicting with other
|
|
units, or the user explicitly
|
|
requested their shut down. If this
|
|
option is set, a unit will be
|
|
automatically cleaned up if no other
|
|
active unit requires it. Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RefuseManualStart=</varname></term>
|
|
<term><varname>RefuseManualStop=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option>
|
|
this unit can only be activated
|
|
(resp. deactivated) indirectly. In
|
|
this case explicit start-up
|
|
(resp. termination) requested by the
|
|
user is denied, however if it is
|
|
started (resp. stopped) as a
|
|
dependency of another unit, start-up
|
|
(resp. termination) will succeed. This
|
|
is mostly a safety feature to ensure
|
|
that the user does not accidentally
|
|
activate units that are not intended
|
|
to be activated explicitly, and not
|
|
accidentally deactivate units that are
|
|
not intended to be deactivated.
|
|
These options default to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>AllowIsolate=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option>
|
|
this unit may be used with the
|
|
<command>systemctl isolate</command>
|
|
command. Otherwise this will be
|
|
refused. It probably is a good idea to
|
|
leave this disabled except for target
|
|
units that shall be used similar to
|
|
runlevels in SysV init systems, just
|
|
as a precaution to avoid unusable
|
|
system states. This option defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>DefaultDependencies=</varname></term>
|
|
|
|
<listitem><para>Takes a boolean
|
|
argument. If <option>true</option>
|
|
(the default), a few default
|
|
dependencies will implicitly be
|
|
created for the unit. The actual
|
|
dependencies created depend on the
|
|
unit type. For example, for service
|
|
units, these dependencies ensure that
|
|
the service is started only after
|
|
basic system initialization is
|
|
completed and is properly terminated on
|
|
system shutdown. See the respective
|
|
man pages for details. Generally, only
|
|
services involved with early boot or
|
|
late shutdown should set this option
|
|
to <option>false</option>. It is
|
|
highly recommended to leave this
|
|
option enabled for the majority of
|
|
common units. If set to
|
|
<option>false</option> this option
|
|
does not disable all implicit
|
|
dependencies, just non-essential
|
|
ones.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>JobTimeoutSec=</varname></term>
|
|
|
|
<listitem><para>When clients are
|
|
waiting for a job of this unit to
|
|
complete, time out after the specified
|
|
time. If this time limit is reached
|
|
the job will be cancelled, the unit
|
|
however will not change state or even
|
|
enter the '<literal>failed</literal>'
|
|
mode. This value defaults to 0 (job
|
|
timeouts disabled), except for device
|
|
units. NB: this timeout is independent
|
|
from any unit-specific timeout (for
|
|
example, the timeout set with
|
|
<varname>Timeout=</varname> in service
|
|
units) as the job timeout has no
|
|
effect on the unit itself, only on the
|
|
job that might be pending for it. Or
|
|
in other words: unit-specific timeouts
|
|
are useful to abort unit state
|
|
changes, and revert them. The job
|
|
timeout set with this option however
|
|
is useful to abort only the job
|
|
waiting for the unit state to
|
|
change.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ConditionPathExists=</varname></term>
|
|
<term><varname>ConditionPathExistsGlob=</varname></term>
|
|
<term><varname>ConditionPathIsDirectory=</varname></term>
|
|
<term><varname>ConditionPathIsSymbolicLink=</varname></term>
|
|
<term><varname>ConditionPathIsMountPoint=</varname></term>
|
|
<term><varname>ConditionDirectoryNotEmpty=</varname></term>
|
|
<term><varname>ConditionFileIsExecutable=</varname></term>
|
|
<term><varname>ConditionKernelCommandLine=</varname></term>
|
|
<term><varname>ConditionVirtualization=</varname></term>
|
|
<term><varname>ConditionSecurity=</varname></term>
|
|
<term><varname>ConditionCapability=</varname></term>
|
|
<term><varname>ConditionNull=</varname></term>
|
|
|
|
<listitem><para>Before starting a unit
|
|
verify that the specified condition is
|
|
true. With
|
|
<varname>ConditionPathExists=</varname>
|
|
a file existence condition can be
|
|
checked before a unit is started. If
|
|
the specified absolute path name does
|
|
not exist, startup of a unit will not
|
|
actually happen, however the unit is
|
|
still useful for ordering purposes in
|
|
this case. The condition is checked at
|
|
the time the queued start job is to be
|
|
executed. If the absolute path name
|
|
passed to
|
|
<varname>ConditionPathExists=</varname>
|
|
is prefixed with an exclamation mark
|
|
(!), the test is negated, and the unit
|
|
is only started if the path does not
|
|
exist.
|
|
<varname>ConditionPathExistsGlob=</varname>
|
|
works in a similar way, but checks for
|
|
the existence of at least one file or
|
|
directory matching the specified
|
|
globbing
|
|
pattern. <varname>ConditionPathIsDirectory=</varname>
|
|
is similar to
|
|
<varname>ConditionPathExists=</varname>
|
|
but verifies whether a certain path
|
|
exists and is a
|
|
directory. <varname>ConditionPathIsSymbolicLink=</varname>
|
|
is similar to
|
|
<varname>ConditionPathExists=</varname>
|
|
but verifies whether a certain path
|
|
exists and is a symbolic
|
|
link. <varname>ConditionPathIsMountPoint=</varname>
|
|
is similar to
|
|
<varname>ConditionPathExists=</varname>
|
|
but verifies whether a certain path
|
|
exists and is a mount
|
|
point. <varname>ConditionFileIsExecutable=</varname>
|
|
is similar to
|
|
<varname>ConditionPathExists=</varname>
|
|
but verifies whether a certain path
|
|
exists, is a regular file and marked
|
|
executable.
|
|
<varname>ConditionDirectoryNotEmpty=</varname>
|
|
is similar to
|
|
<varname>ConditionPathExists=</varname>
|
|
but verifies whether a certain path
|
|
exists and is a non-empty
|
|
directory. Similarly
|
|
<varname>ConditionKernelCommandLine=</varname>
|
|
may be used to check whether a
|
|
specific kernel command line option is
|
|
set (or if prefixed with the
|
|
exclamation mark unset). The argument
|
|
must either be a single word, or an
|
|
assignment (i.e. two words, separated
|
|
by the equality sign). In the former
|
|
case the kernel command line is
|
|
searched for the word appearing as is,
|
|
or as left hand side of an
|
|
assignment. In the latter case the
|
|
exact assignment is looked for with
|
|
right and left hand side
|
|
matching. <varname>ConditionVirtualization=</varname>
|
|
may be used to check whether the
|
|
system is executed in a virtualized
|
|
environment and optionally test
|
|
whether it is a specific
|
|
implementation. Takes either boolean
|
|
value to check if being executed in
|
|
any virtualized environment, or one of
|
|
<varname>vm</varname> and
|
|
<varname>container</varname> to test
|
|
against a specific type of
|
|
virtualization solution, or one of
|
|
<varname>qemu</varname>,
|
|
<varname>kvm</varname>,
|
|
<varname>vmware</varname>,
|
|
<varname>microsoft</varname>,
|
|
<varname>oracle</varname>,
|
|
<varname>xen</varname>,
|
|
<varname>bochs</varname>,
|
|
<varname>chroot</varname>,
|
|
<varname>openvz</varname>,
|
|
<varname>lxc</varname>,
|
|
<varname>systemd-nspawn</varname>,
|
|
<varname>pidns</varname> to test
|
|
against a specific implementation. If
|
|
multiple virtualization technologies
|
|
are nested only the innermost is
|
|
considered. The test may be negated by
|
|
prepending an exclamation mark.
|
|
<varname>ConditionSecurity=</varname>
|
|
may be used to check whether the given
|
|
security module is enabled on the
|
|
system. Currently the only recognized
|
|
value is <varname>selinux</varname>.
|
|
The test may be negated by prepending
|
|
an exclamation
|
|
mark. <varname>ConditionCapability=</varname>
|
|
may be used to check whether the given
|
|
capability exists in the capability
|
|
bounding set of the service manager
|
|
(i.e. this does not check whether
|
|
capability is actually available in
|
|
the permitted or effective sets, see
|
|
<citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details). Pass a capability name
|
|
such as <literal>CAP_MKNOD</literal>,
|
|
possibly prefixed with an exclamation
|
|
mark to negate the check. Finally,
|
|
<varname>ConditionNull=</varname> may
|
|
be used to add a constant condition
|
|
check value to the unit. It takes a
|
|
boolean argument. If set to
|
|
<varname>false</varname> the condition
|
|
will always fail, otherwise
|
|
succeed. If multiple conditions are
|
|
specified the unit will be executed if
|
|
all of them apply (i.e. a logical AND
|
|
is applied). Condition checks can be
|
|
prefixed with a pipe symbol (|) in
|
|
which case a condition becomes a
|
|
triggering condition. If at least one
|
|
triggering condition is defined for a
|
|
unit then the unit will be executed if
|
|
at least one of the triggering
|
|
conditions apply and all of the
|
|
non-triggering conditions. If you
|
|
prefix an argument with the pipe
|
|
symbol and an exclamation mark the
|
|
pipe symbol must be passed first, the
|
|
exclamation second. Except for
|
|
<varname>ConditionPathIsSymbolicLink=</varname>,
|
|
all path checks follow
|
|
symlinks.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Names=</varname></term>
|
|
|
|
<listitem><para>Additional names for
|
|
this unit. The names listed here must
|
|
have the same suffix (i.e. type) as
|
|
the unit file name. This option may be
|
|
specified more than once, in which
|
|
case all listed names are used. Note
|
|
that this option is different from the
|
|
<varname>Alias=</varname> option from
|
|
the [Install] section mentioned
|
|
below. See below for details. Note
|
|
that in almost all cases this option
|
|
is not what you want. A symlink alias
|
|
in the file system is generally
|
|
preferable since it can be used as
|
|
lookup key. If a unit with a symlinked
|
|
alias name is not loaded and needs to
|
|
be it is easily found via the
|
|
symlink. However, if a unit with an
|
|
alias name configured with this
|
|
setting is not loaded it will not be
|
|
discovered. This settings' only use is
|
|
in conjunction with service
|
|
instances.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>Unit file may include a [Install] section, which
|
|
carries installation information for the unit. This
|
|
section is not interpreted by
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
|
during runtime. It is used exclusively by the
|
|
<command>enable</command> and
|
|
<command>disable</command> commands of the
|
|
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
|
tool during installation of a unit:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><varname>Alias=</varname></term>
|
|
|
|
<listitem><para>Additional names this
|
|
unit shall be installed under. The
|
|
names listed here must have the same
|
|
suffix (i.e. type) as the unit file
|
|
name. This option may be specified
|
|
more than once, in which case all
|
|
listed names are used. At installation
|
|
time,
|
|
<command>systemctl enable</command>
|
|
will create symlinks from these names
|
|
to the unit file name. Note that this
|
|
is different from the
|
|
<varname>Names=</varname> option from
|
|
the [Unit] section mentioned above:
|
|
The names from
|
|
<varname>Names=</varname> apply
|
|
unconditionally if the unit is
|
|
loaded. The names from
|
|
<varname>Alias=</varname> apply only
|
|
if the unit has actually been
|
|
installed with the
|
|
<command>systemctl enable</command>
|
|
command. Also, if systemd searches for a
|
|
unit, it will discover symlinked alias
|
|
names as configured with
|
|
<varname>Alias=</varname>, but not
|
|
names configured with
|
|
<varname>Names=</varname> only. It is
|
|
a common pattern to list a name in
|
|
both options. In this case, a unit
|
|
will be active under all names if
|
|
installed, but also if not installed
|
|
but requested explicitly under its
|
|
main name.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>WantedBy=</varname></term>
|
|
|
|
<listitem><para>Installs a symlink in
|
|
the <filename>.wants/</filename>
|
|
subdirectory for a unit. This has the
|
|
effect that when the listed unit name
|
|
is activated the unit listing it is
|
|
activated
|
|
too. <command>WantedBy=foo.service</command>
|
|
in a service
|
|
<filename>bar.service</filename> is
|
|
mostly equivalent to
|
|
<command>Alias=foo.service.wants/bar.service</command>
|
|
in the same file.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Also=</varname></term>
|
|
|
|
<listitem><para>Additional units to
|
|
install when this unit is
|
|
installed. If the user requests
|
|
installation of a unit with this
|
|
option configured,
|
|
<command>systemctl enable</command>
|
|
will automatically install units
|
|
listed in this option as
|
|
well.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.snapshot</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|