[Pacemaker] [Problem] lrmd detects monitor time-out by revision of the system time.

[renayama19661014 at ybb.ne.jp]

Hi Andrew,

I confirmed it in various ways.

The conclusion varies in movement by a version of glib.
 * The problem occurs in RHEL6.x.
 * The problem does not occur in RHEL7.0.

And this problem is solved in glib of a new version.

A change of next glib seems to solve a problem in a new version.
 * https://github.com/GNOME/glib/commit/91113a8aeea40cc2d7dda65b09537980bb602a06#diff-fc9b4bb280a13f8e51c51b434e7d26fd

Many users expect right movement in old glib.
 * Till it shifts to RHEL7...

Do you not make modifications in Pacemaker to support an old version?
 * Model it on old G_xxxx() function.

Best Regards,
Hideo Yamauchi.



----- Original Message -----
> From: Andrew Beekhof <andrew at beekhof.net>
> To: renayama19661014 at ybb.ne.jp
> Cc: The Pacemaker cluster resource manager <pacemaker at oss.clusterlabs.org>
> Date: 2014/9/8, Mon 19:55
> Subject: Re: [Pacemaker] [Problem] lrmd detects monitor time-out by revision of the system time.
> 
> 
> On 8 Sep 2014, at 7:12 pm, renayama19661014 at ybb.ne.jp wrote:
> 
>>  Hi Andrew,
>> 
>>>>>>  I confirmed some problems, but seem to be caused by the 
> fact that 
>> 
>>>  an event 
>>>>>  occurs somehow or other in g_main_loop of lrmd in the period 
> when it is 
>>>  shorter 
>>>>>  than a monitor.
>>>>> 
>>>>>  So if you create a trivial program with g_main_loop and a 
> timer, and 
>>>  then change 
>>>>>  the system time, does the timer expire early?
>>>> 
>>>>  Yes.
>>> 
>>>  That sounds like a glib bug. Ideally we'd get it fixed there rather 
> than 
>>>  work-around it in pacemaker.
>>>  Have you spoken to them at all?
>>> 
>> 
>> 
>>  No.
>>  I investigate glib library a little more.
>>  And I talk with community of glib.
>> 
>>  I may talk again afterwards.
> 
> Cool. I somewhat expect them to say "working as designed".
> Which would be unfortunate, but it shouldn't be too hard to work around.
>