From 41448597f2289c570e96315abf34adab4ff204e1 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 10 Feb 2016 21:30:25 +0100 Subject: man: document distinction between ConditionXYZ= and AssertXYZ= References: #2468 --- man/systemd.unit.xml | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) (limited to 'man/systemd.unit.xml') 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. --> - 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. + 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 AssertArchitecture=, + AssertVirtualization=, … options for a similar mechanism that puts the unit in a failure + state and logs about the failed check (see below). ConditionArchitecture= may be used to check whether the system is running on a specific @@ -1067,14 +1068,12 @@ AssertFileNotEmpty= AssertFileIsExecutable= - Similar to the - ConditionArchitecture=, - ConditionVirtualization=, 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. + Similar to the ConditionArchitecture=, + ConditionVirtualization=, …, 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. -- cgit v1.2.3-54-g00ecf