systemd Unit Files
Wants=
If unit foo.service
specifies Wants=bar.service
, then:
- when foo
is started also bar
is started.
- if bar
fails to start, this has no impact on foo
- this does not enforce a specific order
Requires=
: similar to Wants=
, but declares a stronger dependency.
If unit foo.service
specifies Requires=bar.service
, then:
- if bar
fails to start, then foo
will be stopped
- if foo.service
specifies After=foo.service
and Wants=foo.service
, then
if bar fails to start, foo
will NOT be started.
Before=
, After=
Ordering dependency
If unit foo.service
specifies Before=bar.service
, then:
- bar.service
is delayed until foo.service
is started
- When shutting down, the reverse dependency applies