[Pacemaker] 2 web and 2 db servers both with drbd. Questions concerning the set-up

[Oliver Hoffmann]

Hi Martin,

thanx for your reply.

Sorry, the set-up might be confusing. On web1 runs apache and tomcat
and on db1 runs mysql and postgresql. web1+2 are connected to a switch.
All other connections are via cross-link. Thus if I do one cluster
instead of two, then every node can only reach 2 others but not the 4th
one. Hence the idea with monit.
So, if i.e. web1 fails then the resources would go to web2, which tries
to connect to db2 via the internal line but db2 would be secondary and 
subsequently without a running mysql or postgresql.

Cheers,

Oliver

> Hi Oliver,
> 
> > > I almost have a set-up which looks like this:
> > > 
> > > 
> > >   Master side        Slave side
> > > 
> > >   ---------virtual IP----------
> > >   |                           |
> > > web1----drbd/pacemaker------web2
> > >   |                           |
> > >   internal                 internal
> > >   |                           |
> > >   |                           |
> > > db1----drbd/pacemaker-------db2
> 
> I am not sure if I understand your setup: web1 for apache, web2 for 
> tomcat, db1 for mysql db2 for pgsql? 
> 
> > I have an idea. I don't want automatic fallback btw. So, why not a
> > simple monit, which does a crm standby in case of a failure of the
> > other master/slave pair?
> 
> I would recommend to go with constraints:
> 
> 1. location prefer settings like apache on web1 score 200 and apache
> on web2 score 100  and vice versa for tomcat and again the same with
> the dbms.
> 2.group the resource accordingly.
> 
> HTH,
> Martin
>  
> 
> 
> Oliver Hoffmann <oh at dom.de> wrote on 04.05.2010 16:00:52:
> 
> > [image removed] 
> > 
> > Re: [Pacemaker] 2 web and 2 db servers both with drbd. Questions 
> > concerning the set-up
> > 
> > Oliver Hoffmann 
> > 
> > to:
> > 
> > pacemaker
> > 
> > 04.05.2010 16:02
> > 
> > Please respond to The Pacemaker cluster resource manager 
> > 
> > Am Tue, 4 May 2010 15:02:54 +0200
> > > Hi list,
> > > 
> > > I almost have a set-up which looks like this:
> > > 
> > > 
> > >   Master side        Slave side
> > > 
> > >   ---------virtual IP----------
> > >   |                           |
> > > web1----drbd/pacemaker------web2
> > >   |                           |
> > >   internal                 internal
> > >   |                           |
> > >   |                           |
> > > db1----drbd/pacemaker-------db2
> > > 
> > > 
> > > The web (apache + tomcat) and db (mysql + postgresql) servers have
> > > their data on a drbd device each. The internal connection is for
> > > better performance of the db queries and redundancy. 
> > > 
> > > How do I ensure that web2 AND db2 take the resources if web1
> > > and/or db1 fail?
> > > 
> > > Thanks for input!
> > > 
> > > Regards,
> > > 
> > > Oliver
> > > 
> > > _______________________________________________
> > > Pacemaker mailing list: Pacemaker at oss.clusterlabs.org
> > > http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> > > 
> > > Project Home: http://www.clusterlabs.org
> > > Getting started:
> > > http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> > > 
> > 
> > I have an idea. I don't want automatic fallback btw. So, why not a
> > simple monit, which does a crm standby in case of a failure of the
> > other master/slave pair?
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > _______________________________________________
> > Pacemaker mailing list: Pacemaker at oss.clusterlabs.org
> > http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> > 
> > Project Home: http://www.clusterlabs.org
> > Getting started:
> > http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> 
> 
> 
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