[Pacemaker] 2 node failover cluster + MySQL Master-Master replica setup

[Ruzsinszky Attila]

Hi,

> A MySQL Multi-Master architecture for a 2 node setup brings a lot of
> configuration and administration overhead and has no conflict detection or
> resolution. Integrating such a setup with Pacemaker only adds to the
Yes, I found it.
The real story: I want to learn clustering with a 2 node failover cluster.
I configured the cluster by DMC (DRBD Management Console).
I used the GUI configuring a MySQL service. It was almost unsuccessfull
which wasn't a surprise for me. After that I started to read some HowTo,
WEB page, etc. for help. I found someone from #mysql-nbd channel who
helped me and adviced me using M-M MySQL config but he doesn't know
almost anything about Pacemaker (He uses RH cluster).

After we did the working M-M config I started pacemaker and I could see
MySQL is working. I could connect to the commonIP and I could create a
test DB. Everything seemed all right until I put standby the master node
(from pacemaker point of view). In that moment mysqld started to "blinking"
between working and not working state because pacemaker always restarted
the process.

In the messages file I clould see some lines about missing privs. (RELOAD
and SUPER).

So I'm here now.

> server. Even the LSB script doesn't handle a Multi-Master setup. You'd have
> to write a custom resource agent, and it would probably fit your setup and
> your setup alone, meaning it couldn't be widely used for other setups, I
> know I had to make some modifications to the mysql resource agent and those
> changes were specific to my setup.
No, I don't want to write scripts. I'm not a programmer. I just want
to try out a
new tech for MySQL clustering except MySQL+DRBD.It is clear for me
theoretically. The files of mysqld reside on the common dir. which was switched
by DRBD. Is that right?

> MySQL Cluster is a choice, it could be integrated with Pacemaker, although I
Now I don't want MySQL Cluster. I think it is a bigger task for me.

> Anyways, this is just to get a feel for what's involved in the process, and
> how Pacemaker would fit the picture, at least from my point of view.
OK

> I would recommend all questions related to MySQL Cluster, Replication,
> Multi-Master be directed to the appropriate mailing lists though, and if you
As I mentioned I've got an M-M config from #mysql-nbd.
The recent problem is MySQL (M-M) + Pacemaker.

> want to write a resource agent for a Multi-Master setup, by all means, do
> share :)
No, I don't want. I'm a beginner both in clustering and MySQL.

> Hope this helps.
Yes, of course.

BTW.
If I want to solve the above problem can you help me? Of course with my
strict error messages, config files, etc. I "feel" my M-M config is not
rock stable (I was able to brake the IO or SQL "channel" between the
two mysqld processes) so I don't know whether I want this type of setup.

TIA,
Ruzsi