[systemd-devel] Shutdown behavior follow up

[Jay.Burger at fujitsu.com]

All,

Referring to my last email regarding the systemd shutdown behavior.  I am working on the assumption that the idea of honoring the first shutdown request
is the preferred way to go. If not this email can be ignored.

I have reproduced the same behavior using a fedora 31 machine with systemd v243. I have a proposed fix, including source file change, patch file and sample service
which can be used to both show the problem and show the fix. I am not sure if this is the right forum to attach those files.

If this is the desired behavior, I am wondering  what are my next steps to get this into the next systemd delivery. I have not done this before so I am looking for some instruction?

Thanks in advance,
-Jay

-----Original Message-----
From: Lennart Poettering <lennart at poettering.net> 
Sent: Monday, January 13, 2020 4:33 AM
To: Burger, Jay <Jay.Burger at us.fujitsu.com>
Cc: systemd-devel at lists.freedesktop.org; Dang, James <James.Dang at us.fujitsu.com>; Berger, Daniel <dan.berger at us.fujitsu.com>; Mahabaleshwar, Niranjan <Niranjan.Mahabaleshwar at us.fujitsu.com>
Subject: Re: [systemd-devel] Shutdown behavior

On Fr, 10.01.20 10:56, Jay Burger (jay.burger at us.fujitsu.com) wrote:

> I made the same type of change in the emergency_action() function in v232.
>
> Question 1: Would this be considered a problem with the design, 
> needing an upstream fix? Or would this be considered a particular user 
> issue, to be fixed with an isolated patch, like we have done? If the 
> latter is the answer to this then would this be considered a legit fix 
> for our purposes? Or is there a better way to handle this use case? I 
> know fixing my user services to not fail on the shutdown would be 
> preferable, but pulling teeth is not in my skillset.

Hmm, so what is the expected behaviour here? If one service requires a reboot and another a poweroff, and one is triggered first and the other second, then I can at least think of four policies that make
sense:

1. first requested always wins

2. last requested always wins

3. reboot is the positive outlook, and thus always wins

4. poweorff is the positive outlook, and thus always wins.

Unless I am mistaken we currently implement policy 2. Which one would you prefer? Can you make a good case why it would be better in the general case?

I have the suspicion we should just adopt the best possible policy here and stick to it and not make things needlessly configurable. But it's a matter of discussion which one that is...

> Question 2: I recently found a case where a poweroff shutdown was 
> triggered while the system was in the "starting" state and a service 
> failure occurred during the shutdown. In this case my logic change did 
> not prevent the shutdown from changing to a reboot. This check of the 
> manager_state found the state was still "starting" and the poweroff 
> was again changed to a reboot. Is there a different logic path taken 
> when in the starting state as opposed to the running state?

Not really, no.

Lennart

--
Lennart Poettering, Berlin