[ClusterLabs] Resource Agents: pgsql vs. pgsqlms

[Jehan-Guillaume de Rorthais]

On Thu, 11 Jul 2024 10:17:24 +0200
Oyvind Albrigtsen <oalbrigt at redhat.com> wrote:
[…]
> >Since postgres ha is rather new to us and me having been lucky not
> >having had to deal with perl so far, just reading the agents
> >themselves does not really shed that much light on this issue.  
> The pgsql has seen more testing and usage, so I would use that unless
> there's a specific reason to use PAF instead.
> 
> It's also written in shell, so if you debug by setting trace_ra=1 or
> by running "psc resource debug-<action> --full <rsc>" it will also be easier
> to debug, as it will list all the commands/checks it's running.

PAF will output debug messages if debug is enabled on Pacemaker side (in
/etc/sysconfig/pacemaker or /etc/default/pacemaker).

It is true "debug-<action>" commands are not supported with PAF because they
are focused on non-promotable agents[1]. PAF rely on cluster contexts and
notify actions to make various checks, recovery and node election, which are
not set or triggered when using "debug-<action>" commands.

But this can be emulated I suppose, eg. by setting the `target-role` by hand
and leave the cluster do its magic transitions?

> Only negative is that the documentation for promotional pgsql cluster
> is dated,

Well, PAF documentation is dated as well, they both deserve some documentation
updates from the authors (erm… I swear I'll do).

[1] as far as I remember, I'm interested to know if this not true anymore.