(re)starting of a daemon after package update

Michal Hlavinka mhlavink at redhat.com
Fri Jun 22 08:22:22 UTC 2012

On 06/21/2012 11:01 PM, Reindl Harald wrote:
> Am 21.06.2012 22:52, schrieb Michal Hlavinka:
>> On 06/20/2012 02:37 PM, Reindl Harald wrote:
>>> Am 20.06.2012 14:32, schrieb Björn Persson:
>>>> Michal Hlavinka wrote:
>>>>> Correct approach would be to save state before installation of new
>>>>> version starts and start dovecot (if flag is set) after old version is
>>>>> removed - that would mean %postun script. This does not seem to work on
>>>>> reinstall (the same version is installed) - %postun script is not executed.
>>>> Please also consider what happens when the new version of Dovecot requires a
>>>> new version of some library. RPM will ensure that both packages are updated in
>>>> the same transaction, but if I understand correctly it's not until %posttrans
>>>> that you can be sure that the new library is in place.
>> %postun is sufficient, but it's not executed on package reinstall
>>> one reason more why the cuurent behavior re-starting services
>>> on updates is simply wrong:
>> You complained that service is restarted during update. Well, in this case, restart is not sufficient. We even have
>> to be sure, the service is not running when there are both old and new files in place. Not restarting the service
>> would be "simply wrong"
> is is NOT simpy wrong
> * i am the admin
> * i decide the time when a service is restarted
> * you have no clue what implication a restart of whatever
>    service has in my environment

you have no clue what implication a non-restarted service has

There are not only one-binary-services, some services have several 
binaries running in the same time. For example with master process 
spawning worker processes. They have internal API, when old master 
process starts new worker expecting different API, possibly using 
different configuration or just old worker with updated plugin using 
different api... you'll get your requested disaster and it's what *I* 
call "simply wrong".

Anyway, this discussion in this thread is off-topic.

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