[linux-lvm] [PATCH] Detect systemd at run-time in 69-dm-lvm-metad.rules

[Zdenek Kabelac]

Dne 31. 07. 19 v 12:41 Julian Andres Klode napsal(a):
> On Wed, Jul 31, 2019 at 12:22:38PM +0200, Zdenek Kabelac wrote:
>> Dne 31. 07. 19 v 11:39 Julian Andres Klode napsal(a):
>>>>> I don't see how this has anything to do with lvmetad. There is no lvmetad
>>>>> anymore.
>>>>
>>>> The whole point of 'service' for 'pvscan' is to postone activation of DM
>>>> devices outside of udev rule processing.
>>>>
>>>> So whatever is replacing systemd service in your's systemd-less system must
>>>> provide similar functionality.
>>>>
>>>> There is currently no way to accept autoactivation capability within
>>>> udev-rule processing.
>>>
>>> This has nothing to do with the part of the message you are replying too, and
>>> is nonsense. The code to run pvscan directly is shipped, the change just moves
>>> the decision whether to do that from compile-time to run-time.
>>
>> As long as 'pvscan' is executed with 'auto-activation' option - it can't be
>> run from udev rule.   Any proposal for this needs to first resolve,
>> how to ensure udev will not try to kill running command in the middle of work.
>>
>> Until this is resolved - proposal of this can't be accepted upstream.
> 
> Again: The code is already there. I'm just moving the decision what to pick from
> compile-time to run-time. This is entirely orthogonal to whether the existing code
> works well or not.


So how about making  2 set of  lvm2 packages for Debian.

1st. set build with dependency on systemd libraries.
2nd. is build without dependency on systemd libraries (thus installable for 
non-systemd users)


lvm2 is not (ATM) build with runtime detection of systemd -  it's either 
compiled to work with systemd (expect all the services to be there).

2nd. mode is compilation without systemd world (provided mostly for older
distros).

We do not test 'hybrid' - where lvm2 would be adapting to presence of  systemd 
binaries (and we don't have capacity to test all these combinations)


Regards

Zdenek