[ClusterLabs] Upgrade corosync problem

[Salvatore D'angelo]

Hi everyone,

Thanks for suggestion. Yesterday in Rome was City Holiday and with week end I think I’ll try all your proposal Monday morning
when I go back to office. Thanks again for support I appreciate it a lot.

> On 29 Jun 2018, at 18:20, Jan Pokorný <jpokorny at redhat.com> wrote:
> 
> On 29/06/18 10:00 +0100, Christine Caulfield wrote:
>> On 27/06/18 08:35, Salvatore D'angelo wrote:
>>> One thing that I do not understand is that I tried to compare corosync
>>> 2.3.5 (the old version that worked fine) and 2.4.4 to understand
>>> differences but I haven’t found anything related to the piece of code
>>> that affects the issue. The quorum tool.c and cfg.c are almost the same.
>>> Probably the issue is somewhere else.
>>> 
>> 
>> This might be asking a bit much, but would it be possible to try this
>> using Virtual Machines rather than Docker images? That would at least
>> eliminate a lot of complex variables.
> 
> Salvatore, you can ignore the part below, try following the "--shm"
> advice in other part of this thread.  Also the previous suggestion
> to compile corosync with --small-memory-footprint may be of help,
> but comes with other costs (expect lower throughput).
> 
> 
> Chrissie, I have a plausible explanation and if it's true, then the
> same will be reproduced wherever /dev/shm is small enough.
> 
> If I am right, then the offending commit is
> https://github.com/corosync/corosync/commit/238e2e62d8b960e7c10bfa0a8281d78ec99f3a26
> (present since 2.4.3), and while it arranges things for the better
> in the context of prioritized, low jitter process, it all of
> a sudden prevents as-you-need memory acquisition from the system,
> meaning that the memory consumption constraints are checked immediately
> when the memory is claimed (as it must fit into dedicated physical
> memory in full).  Hence this impact we likely never realized may
> be perceived as a sort of a regression.
> 
> Since we can calculate the approximate requirements statically, might
> be worthy to add something like README.requirements, detailing how much
> space will be occupied for typical configurations at minimum, e.g.:
> 
> - standard + --small-memory-footprint configuration
> - 2 + 3 + X nodes (5?)
> - without any service on top + teamed with qnetd + teamed with
>  pacemaker atop (including just IPC channels between pacemaker
>  daemons and corosync's CPG service, indeed)
> 
> -- 
> Jan (Poki)
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