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.)</para>
+ 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
configuration options. Other specifiers that may be
used are <literal>%n</literal>, <literal>%N</literal>,
<literal>%p</literal>, <literal>%P</literal>,
- <literal>%I</literal> and <literal>%f</literal>, for
+ <literal>%I</literal>, <literal>%f</literal>,
+ <literal>%c</literal>, <literal>%r</literal>,
+ <literal>%R</literal> and <literal>%t</literal> for
the full unit name, the unescaped unit name, the
prefix name, the unescaped prefix name, the unescaped
- instance name and the unescaped filename,
+ instance name, the unescaped filename, the control
+ group path of the unit, the root control group path of
+ systemd, and the parent directory of the root control
+ cgroup path of systemd and the runtime socket dir,
respectively. The unescaped filename is either the
unescaped instance name (if set) with / prepended (if
necessary), or the prefix name similarly prepended
with /. The prefix name here refers to the string
before the @, i.e. "getty" in the example above, where
- "tty3" is the instance name.</para>
+ "tty3" is the instance name. The runtime socket
+ directory is either <filename>/run</filename> (for the
+ system manager) or <literal>$XDG_RUNTIME_DIR</literal>
+ (for user managers).</para>
<para>If a unit file is empty (i.e. has the file size
0) or is symlinked to <filename>/dev/null</filename>
dependent on the type of unit:</para>
<variablelist>
- <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.</para>
- </listitem>
- </varlistentry>
<varlistentry>
<term><varname>Description=</varname></term>
unexpectedly disappear if a service
terminates on its own choice, a device
is unplugged or a mount point
- unmounted with involvement of
+ unmounted without involvement of
systemd.</para></listitem>
</varlistentry>
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>
<varlistentry>
<term><varname>ConditionPathExists=</varname></term>
+ <term><varname>ConditionPathExistsGlob=</varname></term>
+ <term><varname>ConditionPathIsDirectory=</varname></term>
+ <term><varname>ConditionDirectoryNotEmpty=</varname></term>
<term><varname>ConditionKernelCommandLine=</varname></term>
+ <term><varname>ConditionVirtualization=</varname></term>
+ <term><varname>ConditionSecurity=</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 existance condition can be
+ 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
is prefixed with an exclamation mark
(!), the test is negated, and the unit
only started if the path does not
- exist. Similarly
+ exist. <varname>ConditionPathExistsGlob=</varname>
+ work in a similar way, but checks for
+ the existance 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>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, seperated
+ 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,
assignment. In the latter case the
exact assignment is looked for with
right and left hand side
- matching. Finally,
+ 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 virtual environment or one of the
+ <varname>qemu</varname>,
+ <varname>kvm</varname>,
+ <varname>vmware</varname>,
+ <varname>microsoft</varname>,
+ <varname>oracle</varname>,
+ <varname>xen</varname>,
+ <varname>pidns</varname>,
+ <varname>openvz</varname> to test
+ against a specific implementation. 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. Finally,
<varname>ConditionNull=</varname> may
be used to add a constant condition
check value to the unit. It takes a
<varname>false</varname> the condition
will always fail, otherwise
succeed. If multiple conditions are
- specified the unit will be executed
- iff at least one of them applies
- (i.e. a logical OR is
- applied).</para></listitem>
+ 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.</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>