[systemd-devel] Create complete dependency/boot organization map?

[Andrei Borzenkov]

23.10.2015 19:02, Chris Bell пишет:
> Hi all,
>
> I was wondering, is there any way to create a complete
> dependency/ordering map for my entire systemd system?

For starting something "systemd --test" shows all static dependencies 
pulled in by startinggiven unit. For stopping something I do not think 
something like this exists.

> Basically, I'd
> like to be able to see, relatively clearly, what targets are reached and
> when,

Not sure what "when" means. systemd --test dumps jobs that will be 
queued together with dependencies.

> what services are wanted/required by the target, and some

That is also shown by "systemctl list-dependencies".

> dependencies between services. A way to visualize the chain from
> switch-root.target and default.target.
>

switch-root.target is challenging because when you run it after boot you 
have rather different unit definitions. It may be possible to override 
it using SYSTEMD_UNIT_PATH but I do not know how to emulate /run and 
/etc. Also results of generators that were running in initrd are no more 
available.

> I know various functions exist to extract portions of the information I
> need, and they can be used together to get a complete picture, but I
> find it difficult to keep everything organized into something ultimately
> useful. Is there a facility I'm missing? Or is this particular ability
> too complex to be worth implementing?
>
> Thanks!
>
> --Chris
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