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
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. To refer to the instance string from
+ 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 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
- the full unit name, the unescaped unit name, the
- prefix name, the unescaped prefix name, the unescaped
- instance name and the unescaped filename,
- 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>
+ 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>
+ </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>
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>
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>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>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
+ 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
<varname>ConditionPathExists=</varname>
is prefixed with an exclamation mark
(!), the test is negated, and the unit
- only started if the path does not
- exist. <varname>ConditionDirectoryNotEmpty=</varname>
+ 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>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 is
+ 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>
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
- if 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. 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>
~ianmdlvl / elogind.git / blobdiff