[systemd-devel] safe and fast shutdown/reboot

[Andrei Borzenkov]

16.03.2018 08:09, aleivag пишет:
> One other thing that may work, is that you could implement a ExecStop
> action in your service unit, that checks if the system is been shutting
> down (by checking status of {shutdown,reboot,halt}.target

Won't work. Status changes only when job for a unit completes and jobs
are executed in order of dependencies. Actually, jobs are *queued* in
order of dependencies so nothing would indicate that you are going to
shutdown until it is too late (i.e. all normal services are stopped).

> [or maybe also
> the runlevel may work?]),

Logically runlevel is not changed until *after* new runlevel has been
reached. Practically systemd does not update runlevel during shutdown at
all.

> and kill the unit if there is one of those
> operations.
> 
> 
> Alvaro Leiva
> 
> On Thu, Mar 15, 2018 at 9:14 PM, Zeal Jagannatha <zealjagannatha at gmail.com>
> wrote:
> 
>> Hmm. This is probably not ideal, but you could hook a 'Type=oneshot'
>> service into shutdown.target which runs 'systemctl kill {your
>> service}.service'.
>>
>> I'm not sure if there's a simpler way to do this using targets.
>>
>> On Thu, Mar 15, 2018 at 8:57 PM prashantkumar dhotre <
>> prashantkumardhotre at gmail.com> wrote:
>>
>>> Thanks but I want to sigkill my services only during system shutdown and
>>> not on normal service stop 'systemctl myservice stop'.
>>> so I can not use ' KillSignal' setting. Is there any other way ?
>>>
>>> On Fri, Mar 16, 2018 at 9:23 AM, Zeal Jagannatha <
>>> zealjagannatha at gmail.com> wrote:
>>>
>>>> I think it would be better for the services you define to specifically
>>>> define their own `KillSignal` so you can control how they shutdown.
>>>> https://www.freedesktop.org/software/systemd/man/systemd.
>>>> kill.html#KillSignal=
>>>>
>>>> It's may not be safe for all the services on the machine to be shut down
>>>> with SIGKILL, so you should avoid using '--force' unless you know that
>>>> everything running on the system is safe to shutdown with SIGKILL.
>>>>
>>>> On Thu, Mar 15, 2018 at 8:43 PM prashantkumar dhotre <
>>>> prashantkumardhotre at gmail.com> wrote:
>>>>
>>>>> Hi
>>>>> I see that default reboot/systemctl reboot command issues SIGTERM to my
>>>>> apps and hence it is doing graceful stop of apps and this may take some
>>>>> time and hence shutdown time may be little longer.
>>>>>
>>>>> I am looking for safe and fastest shutdown/reboot method.
>>>>>
>>>>>
>>>>> a) It is OK if my apps are stopped ungracefully during shutdown .(app
>>>>> should not start automatically again after they are killed/stopped during
>>>>> shutdown)
>>>>>
>>>>> b)  file system and such system level stuff needs to be cleanly shut
>>>>> down
>>>>>
>>>>> 1) From my research, I see that 'systemctl reboot --force' is the one I
>>>>> can use.
>>>>> I understand that this command sends SIGKILL to my apps.
>>>>> So this satisfies both (a) and (b) and hence this command should be
>>>>> used to reboot faster.
>>>>> Could you please confirm ?
>>>>> If this is not right method, please comment on which method to use.
>>>>>
>>>>> 2) Also is there a way to limit SIGKILL to only my apps when I do ' 'systemctl
>>>>> reboot --force'
>>>>> so that rest of the system level services still get stopped gracefully
>>>>>
>>>>> 3) If  'systemctl reboot --force' is correct command to use in my
>>>>> case, then during shutdown , will my apps get restarted
>>>>> due to 'Restart'/'StartLimitBurst'/'StartLimitInterval' settings in
>>>>> service file ? I dont want my apps to get restarted if they are
>>>>> stopped/killed during system shutdown
>>>>>
>>>>>
>>>>> Thanks
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> systemd-devel mailing list
>>>>> systemd-devel at lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/systemd-devel
>>>>>
>>>>
>>>
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>> https://lists.freedesktop.org/mailman/listinfo/systemd-devel
>>
>>
> 
> 
> 
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