[Pacemaker] Signal hangup handling for pacemaker and corosync

[Andrew Beekhof]

On 21 Jul 2014, at 3:45 pm, Vladislav Bogdanov <bubble at hoster-ok.com> wrote:

> 21.07.2014 08:36, Andrew Beekhof wrote:
>> 
>> On 21 Jul 2014, at 2:50 pm, Vladislav Bogdanov <bubble at hoster-ok.com> wrote:
>> 
>>> 21.07.2014 06:28, Andrew Beekhof wrote:
>>>> 
>>>> On 15 Jul 2014, at 8:45 pm, Arjun Pandey <apandepublic at gmail.com> wrote:
>>>> 
>>>>> On Tue, Jul 15, 2014 at 3:36 PM, Andrew Beekhof <andrew at beekhof.net> wrote:
>>>>>> 
>>>>>> On 15 Jul 2014, at 8:00 pm, Arjun Pandey <apandepublic at gmail.com> wrote:
>>>>>> 
>>>>>>> Right. Actually the issue i am facing is that i am starting the
>>>>>>> pacemaker service remotely from a wrapper and thus pacemakerd dies
>>>>>>> when the wrapper exits.nohup solves the problem but then HUP cannot be
>>>>>>> used by pacemaker. Is this workaround ok ?
>>>>>> 
>>>>>> I guess. How are you starting pacemaker?  Usually its with some variant of 'service pacemaker start'.
>>>>> I am using 'service pacemaker start'. However this is being called
>>>>> from my script. So when the script exits pacemaker gets SIGHUP.
>>>> 
>>>> Release testing starts clusters as:
>>>> 
>>>>  ssh -l root somenode -- service pacemaker start
>>> 
>>> It could depend on what "service" is.
>>> It would either schedule systemd to run job (el7/fc18+), or just run
>>> init script itself (el6). In latter case, if process didn't detach from
>>> its controlling terminal when that terminal gone away, it will be sent a
>>> SIGHUP.
>> 
>> Except we test rhel6 the same way...
> 
> I understand. This issue is from "sometimes happens on some systems"
> folder. I recall I had problems ages ago with a daemon run from rc.local
> sometimes exists with HUP. 'sleep 1' after its launch was the easiest fix.

How about: https://github.com/beekhof/pacemaker/commit/95175f5

> 
>> 
>>> I'd recommend adding HUP handler (f.e. ignore) or/and detach
>>> (setsid()) right before daemonizing.
>>> 
>>>> 
>>>> And I've never seen the behaviour you speak of.
>>>> How is what you're doing different?
>>>> 
>>>>>> 
>>>>>>> 
>>>>>>> I was checking out the current pacemaker code.setsid is called for
>>>>>>> each child process.However if we do this for main process to then it
>>>>>>> will also be detached from the terminal.
>>>>>>> 
>>>>>>> Regards
>>>>>>> Arjun
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> On Tue, Jul 15, 2014 at 3:01 PM, Andrew Beekhof <andrew at beekhof.net> wrote:
>>>>>>>> 
>>>>>>>> On 15 Jul 2014, at 7:13 pm, Arjun Pandey <apandepublic at gmail.com> wrote:
>>>>>>>> 
>>>>>>>>> Hi Andrew
>>>>>>>>> 
>>>>>>>>> AFAIK linux daemons don't terminate on SIGHUP.
>>>>>>>> 
>>>>>>>> Read the man page, POSIX specifies that the default action is 'term' ie. 'terminate'.
>>>>>>>> 
>>>>>>>>> They typically reload
>>>>>>>>> configuration on receiving this signal.Eg- rsyslogd. I thought it was
>>>>>>>>> safe to make this assumption here as well.
>>>>>>>> 
>>>>>>>> Not anywhere as it turns out
>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> Regards
>>>>>>>>> Arjun
>>>>>>>>> 
>>>>>>>>> On Tue, Jul 15, 2014 at 2:15 PM, Andrew Beekhof <andrew at beekhof.net> wrote:
>>>>>>>>>> 
>>>>>>>>>> On 15 Jul 2014, at 6:19 pm, Arjun Pandey <apandepublic at gmail.com> wrote:
>>>>>>>>>> 
>>>>>>>>>>> Hi all
>>>>>>>>>>> 
>>>>>>>>>>> I am running pacemaker version 1.1.10-14.el6 on CentOS 6. On setting
>>>>>>>>>>> up cluster if I send SIGHUP to either pacemaker or corosync services ,
>>>>>>>>>>> they die.
>>>>>>>>>>> Is this a bug ? What is the intension behind this behavior?
>>>>>>>>>> 
>>>>>>>>>> Standard default I believe.
>>>>>>>>>> Have you run 'man 7 signal' lately?
>>>>>>>>>> 
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>>>>>>>>>> 
>>>>>>>>> 
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>>>>>>>> 
>>>>>>>> 
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>>>>>>>> 
>>>>>>> 
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>>>>>> 
>>>>>> 
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>>>>>> 
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>>>>>> 
>>>>> 
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>>>>> Bugs: http://bugs.clusterlabs.org
>>>> 
>>>> 
>>>> 
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>>>> 
>>> 
>>> 
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>> 
>> 
>> 
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>> 
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>> Bugs: http://bugs.clusterlabs.org
>> 
> 
> 
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