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authorLennart Poettering <lennart@poettering.net>2016-02-10 21:30:25 +0100
committerLennart Poettering <lennart@poettering.net>2016-02-10 23:48:46 +0100
commit41448597f2289c570e96315abf34adab4ff204e1 (patch)
tree83c0c20919f4e4b9afcd5ff442d74a2cc5f6dc16
parent6e004630fea24f1d4d76f8b062f9f862ba237140 (diff)
man: document distinction between ConditionXYZ= and AssertXYZ=
References: #2468
-rw-r--r--man/systemd.unit.xml29
1 files changed, 14 insertions, 15 deletions
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 46b288f20b..04c4515cd9 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -827,13 +827,14 @@
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 +1068,12 @@
<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>