Re: how to configure multi-master

[Buchan Milne <bgmilne@staff.telkomsa.net>]

On Sunday 20 July 2008 22:12:38 Liutauras Adomaitis wrote:
> On Sat, Jul 19, 2008 at 11:19 AM, Dieter Kluenter <dieter@dkluenter.de>
>
> wrote:
> > Hi,
> >
> > "Liutauras Adomaitis" <liutauras.adomaitis@gmail.com> writes:
> > > Hello,
> > >
> > > I feel a little bit spaming this list, but still - how to setup
> >
> > multi-master?
> >
> > > Reading
> > > http://www.zytrax.com/books/ldap/ch7/#ol-syncrepl
> > > http://www.openldap.org/doc/admin24/replication.html
> > > gave me impression that simply adding serverID in global (above
> > > database) section, syncrepl and overlay syncprov in database section
> > > should give me multi master setup. THis did worked - meaning I got the
> > > same data on both servers, but I couldn't make updates to either of
> > > servers. Google says absolutely nothing about that. The error is
> > > "shadow context; no update referral at ..." Adding updateref directive
> > > to conf file seemed to me
> >
> > wrong,
> >
> > > because multi master is meant to be multi write nodes setup, so I
> > > didn't
> >
> > tried
> >
> > > that. After about four hours of searching for any full working example
> > > of multi-master implementation I decided to put mirror mode true on
> > > both
> >
> > servers
> >
> > > at the end of conf file - that did the trick.
> > > So do I need add mirror mode or not? It is not clear the difference of
> > > multi-master and mirror mode, which I asked on different message.
> > > I didn't tried setting mirror mode false and see if updates are
> > > working,
> >
> > but
> >
> > > if this is what I missed, then it is very strange, that official
> > > administrators guide is missing such a key point.
> >
> > Multi-way replication and mirror mode are two different
> > aproaches. While ldap servers configured for n-way replication are
> > all visible and available by all clients and all allowing all
> > operations. Mirror mode is a sort of backup and standby system. Only
> > one ldap server should be visible and available, thus allowing write
> > operations, while the second ldap-server is in hot standby position,
> > and only available to clients if the first server fails.
> > Run test050 to get simple configuration examples for n-way
> > replication. For mirror mode configuration see
> > http://www.openldap.org/doc/admin24/replication.html, part 17.3.2 and
> > 17.4.4
>
> Your explanation has answered the other my question "difference between
> multi master and mirror mode".
>
> I was always using Mandriva rpms and never compiled openldap by myself. But
> few days ago I did compiling of openldap srpm and saw it doing some tests.

No need to compile to get the tests, just 'urpmi openldap-tests', and as a 
normal (non-root) user you should be able to run all the tests as follows:

$ make -C /usr/share/openldap/tests/ tests

Note that it is configured to work in $TMP/openldap-testrun by default. For 
your purposes, you may want to:

$ cd /usr/share/openldap/tests
$ ./run test050

Now look in $TMP/openldap-testrun

> I'm going to dig arround for how to make this test050 on Mandriva.

No need to dig, as we ship the tests ready-to-run ...

BTW, 2.4.11 is available in backports for 2008.1 as of Friday.

Regards,
Buchan