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| Copyright 2010 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
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| |
| <refentry id="systemd.unit"> |
| |
| <refentryinfo> |
| <title>systemd.unit</title> |
| <productname>systemd</productname> |
| |
| <authorgroup> |
| <author> |
| <contrib>Developer</contrib> |
| <firstname>Lennart</firstname> |
| <surname>Poettering</surname> |
| <email>lennart@poettering.net</email> |
| </author> |
| </authorgroup> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>systemd.unit</refentrytitle> |
| <manvolnum>5</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>systemd.unit</refname> |
| <refpurpose>Unit configuration</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <para><filename>systemd.service</filename>, |
| <filename>systemd.socket</filename>, |
| <filename>systemd.device</filename>, |
| <filename>systemd.mount</filename>, |
| <filename>systemd.automount</filename>, |
| <filename>systemd.swap</filename>, |
| <filename>systemd.target</filename>, |
| <filename>systemd.path</filename>, |
| <filename>systemd.timer</filename>, |
| <filename>systemd.snapshot</filename></para> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para>A unit configuration file encodes information |
| about a service, a socket, a device, a mount point, an |
| automount point, a swap file or partition, a start-up |
| target, a file system path or a timer controlled and |
| supervised by |
| <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>. The |
| syntax is inspired by <ulink |
| url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG |
| Desktop Entry Specification</ulink> <filename>.desktop</filename> files, which are in turn |
| inspired by Microsoft Windows |
| <filename>.ini</filename> files.</para> |
| |
| <para>This man pages lists the common configuration |
| options of all the unit types. These options need to |
| be configured in the [Unit] resp. [Install] |
| section of the unit files.</para> |
| |
| <para>In addition to the generic [Unit] and [Install] |
| sections described here, each unit should have a |
| type-specific section, e.g. [Service] for a service |
| unit. See the respective man pages for more |
| information.</para> |
| |
| <para>Unit files may contain additional options on top |
| of those listed here. If systemd encounters an unknown |
| option it will write a warning log message but |
| continue loading the unit. If an option is prefixed |
| with <option>X-</option> it is ignored completely by |
| systemd. Applications may use this to include |
| additional information in the unit files.</para> |
| |
| <para>Boolean arguments used in unit files can be |
| written in various formats. For positive settings the |
| strings <option>1</option>, <option>yes</option>, |
| <option>true</option> and <option>on</option> are |
| equivalent. For negative settings the strings |
| <option>0</option>, <option>no</option>, |
| <option>false</option> and <option>off</option> are |
| equivalent.</para> |
| |
| <para>Time span values encoded in unit files can be |
| written in various formats. A stand-alone number |
| specifies a time in seconds. If suffixed with a time |
| unit, the unit is honored. A concatenation of |
| multiple values with units is supported, in which case |
| the values are added up. Example: "50" refers to 50 |
| seconds; "2min 200ms" refers to 2 minutes plus 200 |
| milliseconds, i.e. 120200ms. The following time units |
| are understood: s, min, h, d, w, ms, us.</para> |
| |
| <para>Empty lines and lines starting with # or ; are |
| ignored. This may be used for commenting. Lines ending |
| in a backslash are concatenated with the following |
| line while reading and the backslash is replaced by a |
| space character. This may be used to wrap long lines.</para> |
| |
| <para>If a line starts with <option>.include</option> |
| followed by a file name, the specified file will be |
| parsed at this point. Make sure that the file that is |
| included has the appropriate section headers before |
| any directives.</para> |
| |
| <para>Along with a unit file |
| <filename>foo.service</filename> a directory |
| <filename>foo.service.wants/</filename> may exist. All |
| units symlinked from such a directory are implicitly |
| added as dependencies of type |
| <varname>Wanted=</varname> to the unit. This is useful |
| to hook units into the start-up of other units, |
| without having to modify their unit configuration |
| files. For details about the semantics of |
| <varname>Wanted=</varname> see below. The preferred |
| way to create symlinks in the |
| <filename>.wants/</filename> directory of a service is |
| with the <command>enable</command> command of the |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| tool which reads information from the [Install] |
| section of unit files. (See below.) A similar |
| functionality exists for <varname>Requires=</varname> |
| type dependencies as well, the directory suffix is |
| <filename>.requires/</filename> in this case.</para> |
| |
| <para>Note that while systemd offers a flexible |
| dependency system between units it is recommended to |
| use this functionality only sparsely and instead rely |
| on techniques such as bus-based or socket-based |
| activation which makes dependencies implicit, which |
| both results in a simpler and more flexible |
| system.</para> |
| |
| <para>Some unit names reflect paths existing in the |
| file system name space. Example: a device unit |
| <filename>dev-sda.device</filename> refers to a device |
| with the device node <filename>/dev/sda</filename> in |
| the file system namespace. If this applies a special |
| way to escape the path name is used, so that the |
| result is usable as part of a file name. Basically, |
| given a path, "/" is replaced by "-", and all |
| unprintable characters and the "-" are replaced by |
| C-style "\x20" escapes. The root directory "/" is |
| encoded as single dash, while otherwise the initial |
| and ending "/" is removed from all paths during |
| transformation. This escaping is reversible.</para> |
| |
| <para>Optionally, units may be instantiated from a |
| template file at runtime. This allows creation of |
| multiple units from a single configuration file. If |
| systemd looks for a unit configuration file it will |
| first search for the literal unit name in the |
| filesystem. If that yields no success and the unit |
| name contains an @ character, systemd will look for a |
| unit template that shares the same name but with the |
| instance string (i.e. the part between the @ character |
| and the suffix) removed. Example: if a service |
| <filename>getty@tty3.service</filename> is requested |
| and no file by that name is found, systemd will look |
| for <filename>getty@.service</filename> and |
| instantiate a service from that configuration file if |
| it is found.</para> |
| |
| <para>To refer to the instance string from |
| within the configuration file you may use the special |
| <literal>%i</literal> specifier in many of the |
| configuration options. Other specifiers exist, the |
| full list is:</para> |
| |
| <table> |
| <title>Specifiers available in unit files</title> |
| <tgroup cols='3' align='left' colsep='1' rowsep='1'> |
| <colspec colname="spec" /> |
| <colspec colname="mean" /> |
| <colspec colname="detail" /> |
| <thead> |
| <row> |
| <entry>Specifier</entry> |
| <entry>Meaning</entry> |
| <entry>Details</entry> |
| </row> |
| </thead> |
| <tbody> |
| <row> |
| <entry><literal>%n</literal></entry> |
| <entry>Full unit name</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%N</literal></entry> |
| <entry>Unescaped full unit name</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%p</literal></entry> |
| <entry>Prefix name</entry> |
| <entry>This refers to the string before the @, i.e. "getty" in the example above, where "tty3" is the instance name.</entry> |
| </row> |
| <row> |
| <entry><literal>%P</literal></entry> |
| <entry>Unescaped prefix name</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%i</literal></entry> |
| <entry>Instance name</entry> |
| <entry>This is the string between the @ character and the suffix.</entry> |
| </row> |
| <row> |
| <entry><literal>%I</literal></entry> |
| <entry>Unescaped instance name</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%f</literal></entry> |
| <entry>Unescaped file name</entry> |
| <entry>This is either the unescaped instance name (if set) with / prepended (if necessary), or the prefix name similarly prepended with /.</entry> |
| </row> |
| <row> |
| <entry><literal>%c</literal></entry> |
| <entry>Control group path of the unit</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%r</literal></entry> |
| <entry>Root control group path of systemd</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%R</literal></entry> |
| <entry>Parent directory of the root control group path of systemd</entry> |
| <entry></entry> |
| </row> |
| <row> |
| <entry><literal>%t</literal></entry> |
| <entry>Runtime socket dir</entry> |
| <entry>This is either /run (for the system manager) or $XDG_RUNTIME_DIR (for user managers).</entry> |
| </row> |
| <row> |
| <entry><literal>%u</literal></entry> |
| <entry>User name</entry> |
| <entry>This is the name of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry> |
| </row> |
| <row> |
| <entry><literal>%h</literal></entry> |
| <entry>User home directory</entry> |
| <entry>This is the home directory of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry> |
| </row> |
| <row> |
| <entry><literal>%s</literal></entry> |
| <entry>User shell</entry> |
| <entry>This is the shell of the configured user of the unit, or (if none is set) the user running the systemd instance.</entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| |
| <para>If a unit file is empty (i.e. has the file size |
| 0) or is symlinked to <filename>/dev/null</filename> |
| its configuration will not be loaded and it appears |
| with a load state of <literal>masked</literal>, and |
| cannot be activated. Use this as an effective way to |
| fully disable a unit, making it impossible to start it |
| even manually.</para> |
| |
| <para>The unit file format is covered by the |
| <ulink |
| url="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise">Interface |
| Stability Promise</ulink>.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Options</title> |
| |
| <para>Unit file may include a [Unit] section, which |
| carries generic information about the unit that is not |
| dependent on the type of unit:</para> |
| |
| <variablelist> |
| |
| <varlistentry> |
| <term><varname>Description=</varname></term> |
| <listitem><para>A free-form string |
| describing the unit. This is intended |
| for use in UIs to show descriptive |
| information along with the unit |
| name.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Documentation=</varname></term> |
| <listitem><para>A space separated list |
| of URIs referencing documentation for |
| this unit or its |
| configuration. Accepted are only URIs |
| of the types |
| <literal>http://</literal>, |
| <literal>https://</literal>, |
| <literal>file:</literal>, |
| <literal>info:</literal>, |
| <literal>man:</literal>. For more |
| information about the syntax of these |
| URIs see |
| <citerefentry><refentrytitle>uri</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Requires=</varname></term> |
| |
| <listitem><para>Configures requirement |
| dependencies on other units. If this |
| unit gets activated, the units listed |
| here will be activated as well. If one |
| of the other units gets deactivated or |
| its activation fails, this unit will |
| be deactivated. This option may be |
| specified more than once, in which |
| case requirement dependencies for all |
| listed names are created. Note that |
| requirement dependencies do not |
| influence the order in which services |
| are started or stopped. This has to be |
| configured independently with the |
| <varname>After=</varname> or |
| <varname>Before=</varname> options. If |
| a unit |
| <filename>foo.service</filename> |
| requires a unit |
| <filename>bar.service</filename> as |
| configured with |
| <varname>Requires=</varname> and no |
| ordering is configured with |
| <varname>After=</varname> or |
| <varname>Before=</varname>, then both |
| units will be started simultaneously |
| and without any delay between them if |
| <filename>foo.service</filename> is |
| activated. Often it is a better choice |
| to use <varname>Wants=</varname> |
| instead of |
| <varname>Requires=</varname> in order |
| to achieve a system that is more |
| robust when dealing with failing |
| services.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>RequiresOverridable=</varname></term> |
| |
| <listitem><para>Similar to |
| <varname>Requires=</varname>. |
| Dependencies listed in |
| <varname>RequiresOverridable=</varname> |
| which cannot be fulfilled or fail to |
| start are ignored if the startup was |
| explicitly requested by the user. If |
| the start-up was pulled in indirectly |
| by some dependency or automatic |
| start-up of units that is not |
| requested by the user this dependency |
| must be fulfilled and otherwise the |
| transaction fails. Hence, this option |
| may be used to configure dependencies |
| that are normally honored unless the |
| user explicitly starts up the unit, in |
| which case whether they failed or not |
| is irrelevant.</para></listitem> |
| |
| </varlistentry> |
| <varlistentry> |
| <term><varname>Requisite=</varname></term> |
| <term><varname>RequisiteOverridable=</varname></term> |
| |
| <listitem><para>Similar to |
| <varname>Requires=</varname> |
| resp. <varname>RequiresOverridable=</varname>. However, |
| if a unit listed here is not started |
| already it will not be started and the |
| transaction fails |
| immediately.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Wants=</varname></term> |
| |
| <listitem><para>A weaker version of |
| <varname>Requires=</varname>. A unit |
| listed in this option will be started |
| if the configuring unit is. However, |
| if the listed unit fails to start up |
| or cannot be added to the transaction |
| this has no impact on the validity of |
| the transaction as a whole. This is |
| the recommended way to hook start-up |
| of one unit to the start-up of another |
| unit. Note that dependencies of this |
| type may also be configured outside of |
| the unit configuration file by |
| adding a symlink to a |
| <filename>.wants/</filename> directory |
| accompanying the unit file. For |
| details see above.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>BindsTo=</varname></term> |
| |
| <listitem><para>Configures requirement |
| dependencies, very similar in style to |
| <varname>Requires=</varname>, however |
| in addition to this behaviour it also |
| declares that this unit is stopped |
| when any of the units listed suddenly |
| disappears. Units can suddenly, |
| unexpectedly disappear if a service |
| terminates on its own choice, a device |
| is unplugged or a mount point |
| unmounted without involvement of |
| systemd.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Conflicts=</varname></term> |
| |
| <listitem><para>Configures negative |
| requirement dependencies. If a unit |
| has a |
| <varname>Conflicts=</varname> setting |
| on another unit, starting the former |
| will stop the latter and vice |
| versa. Note that this setting is |
| independent of and orthogonal to the |
| <varname>After=</varname> and |
| <varname>Before=</varname> ordering |
| dependencies.</para> |
| |
| <para>If a unit A that conflicts with |
| a unit B is scheduled to be started at |
| the same time as B, the transaction |
| will either fail (in case both are |
| required part of the transaction) or |
| be modified to be fixed (in case one |
| or both jobs are not a required part |
| 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 |
| conflicted is |
| 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 |
| <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 |
| 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>PropagatesReloadTo=</varname></term> |
| <term><varname>ReloadPropagatedFrom=</varname></term> |
| |
| <listitem><para>Lists one or more |
| units where reload requests on the |
| unit will be propagated to/on the |
| other unit will be propagated |
| from. Issuing a reload request on a |
| unit will automatically also enqueue a |
| reload request on all units that the |
| reload request shall be propagated to |
| via these two |
| settings.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>RequiresMountsFor=</varname></term> |
| |
| <listitem><para>Takes a space |
| separated list of paths. Automatically |
| adds dependencies of type |
| <varname>Requires=</varname> and |
| <varname>After=</varname> for all |
| mount units required to access the |
| specified path.</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>ConditionPathIsReadWrite=</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>ConditionPathIsReadWrite=</varname> |
| is similar to |
| <varname>ConditionPathExists=</varname> |
| but verifies whether the underlying |
| file system is read and writable |
| (i.e. not mounted |
| read-only). <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>lxc-libvirt</varname>, |
| <varname>systemd-nspawn</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>SourcePath=</varname></term> |
| <listitem><para>A path to a |
| configuration file this unit has been |
| generated from. This is primarily |
| useful for implementation of generator |
| tools that convert configuration from |
| an external configuration file format |
| into native unit files. Thus |
| functionality should not be used in |
| normal units.</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.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>WantedBy=</varname></term> |
| <term><varname>RequiredBy=</varname></term> |
| |
| <listitem><para>Installs a symlink in |
| the <filename>.wants/</filename> |
| resp. <filename>.requires/</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> |