diff options
Diffstat (limited to 'man/systemd.unit.xml')
| -rw-r--r-- | man/systemd.unit.xml | 65 |
1 files changed, 29 insertions, 36 deletions
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml index 46b288f20b..16aded89d1 100644 --- a/man/systemd.unit.xml +++ b/man/systemd.unit.xml @@ -178,18 +178,14 @@ directory suffix is <filename>.requires/</filename> in this case.</para> - <para>Along with a unit file <filename>foo.service</filename>, a - directory <filename>foo.service.d/</filename> may exist. All files - with the suffix <literal>.conf</literal> from this directory will - be parsed after the file itself is parsed. This is useful to alter - or add configuration settings to a unit, without having to modify - their unit files. Make sure that the file that is included has the - appropriate section headers before any directive. Note that, for - instanced units, this logic will first look for the instance - <literal>.d/</literal> subdirectory and read its - <literal>.conf</literal> files, followed by the template - <literal>.d/</literal> subdirectory and reads its - <literal>.conf</literal> files.</para> + <para>Along with a unit file <filename>foo.service</filename>, a "drop-in" directory + <filename>foo.service.d/</filename> may exist. All files with the suffix <literal>.conf</literal> from this + directory will be parsed after the file itself is parsed. This is useful to alter or add configuration settings to + a unit, without having to modify their unit files. Make sure that the file that is included has the appropriate + section headers before any directive. Note that for instanced units, this logic will first look for the instance + <literal>.d/</literal> subdirectory and read its <literal>.conf</literal> files, followed by the template + <literal>.d/</literal> subdirectory and reads its <literal>.conf</literal> files. Also note that settings from the + <literal>[Install]</literal> section are not available in drop-in unit files, and have no effect.</para> <para>In addition to <filename>/etc/systemd/system</filename>, the drop-in <literal>.conf</literal> files for system services @@ -827,13 +823,14 @@ useful and probably just confusing. --> - <listitem><para>Before starting a unit verify that the - specified condition is true. If it is not true, the starting - of the unit will be skipped, however all ordering dependencies - of it are still respected. A failing condition will not result - in the unit being moved into a failure state. The condition is - checked at the time the queued start job is to be - executed.</para> + <listitem><para>Before starting a unit, verify that the specified condition is true. If it is not true, the + starting of the unit will be (mostly silently) skipped, however all ordering dependencies of it are still + respected. A failing condition will not result in the unit being moved into a failure state. The condition is + checked at the time the queued start job is to be executed. Use condition expressions in order to silently skip + units that do not apply to the local running system, for example because the kernel or runtime environment + doesn't require its functionality. Use the various <varname>AssertArchitecture=</varname>, + <varname>AssertVirtualization=</varname>, … options for a similar mechanism that puts the unit in a failure + state and logs about the failed check (see below).</para> <para><varname>ConditionArchitecture=</varname> may be used to check whether the system is running on a specific @@ -1067,14 +1064,12 @@ <term><varname>AssertFileNotEmpty=</varname></term> <term><varname>AssertFileIsExecutable=</varname></term> - <listitem><para>Similar to the - <varname>ConditionArchitecture=</varname>, - <varname>ConditionVirtualization=</varname>, etc., condition - settings described above, these settings add assertion checks - to the start-up of the unit. However, unlike the conditions - settings, any assertion setting that is not met results in - failure of the start job it was triggered - by.</para></listitem> + <listitem><para>Similar to the <varname>ConditionArchitecture=</varname>, + <varname>ConditionVirtualization=</varname>, …, condition settings described above, these settings add + assertion checks to the start-up of the unit. However, unlike the conditions settings, any assertion setting + that is not met results in failure of the start job it was triggered by (which means this is logged about + loudly). Use assertion expressions for units that cannot operate when specific requirements are not met, and + where this is something the administrator or user should look into.</para></listitem> </varlistentry> <varlistentry> @@ -1094,15 +1089,13 @@ <refsect1> <title>[Install] Section Options</title> - <para>Unit file may include an <literal>[Install]</literal> - 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> + <para>Unit files may include an <literal>[Install]</literal> 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 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. Note that settings in the <literal>[Install]</literal> section may not appear in + <filename>.d/*.conf</filename> unit file drop-ins (see above).</para> <variablelist class='unit-directives'> <varlistentry> |