Am 02.01.19 um 04:13 schrieb James Feeney: >> It's about Requires and After. I think a unit in Requires should imply >> that unit in After too, otherwise the requirement isn't really met. >> Is there a use case for Requires but not After? > > Olaf, previously, on GitHub, you had said: > >>> I think I understand Requires and After ... > > and, I would suggest that, no - or you would not be asking this question. > > systemd has two different classes of "dependencies": 1) "activation" > dependencies, and 2) "ordering" dependencies. > > An activation dependency does not, a priori, have to obey any rules about > ordering. There are not, automatically, any promises or guarantees about in > what order service units, for instance, might be queued for execution, based > upon a Requires= dependency. > > "Ordering" is an independent characteristic from "Activation". "Activation" > only promises to enqueue a unit, and then, only if the unit is some kind of > unit that can be "executed", such as a timer or service unit. In contrast, > for instance, systemd is only a "passive observer" of a device unit. > "enqueuing" a device unit for "activation" would make no sense in this > context. A *service* unit that *creates* a device unit could be enqueued for > activation, but not the device unit itself.
but this has no logic at all "After" is a soft dependency, if that unit isn't enabled or don#t exist at all it don't matter "Requires" is a hard dependency and it makes no sense not imply ordering _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
