[Pacemaker] Master/Slave Confusion

Moritz Krinke mkrinke at fotocommunity.net
Mon Feb 1 05:49:03 EST 2010


if you make the LDAP daemon listen on all available interfaces, it will accept connections on the on-demand activated floating-ip.

Or, if you really want to make the ldap daemon listen only on the floating-ip, you would have to write a resoure agent for ldap which will edit the ldap config (add the floating ip) and restart the ldap daemon on a promote, and remove it again on a denote. this way you would have the ldap daemon listening on the fix ip for replication on the slave and only if promoted on the floating-ip.

Am 01.02.2010 um 03:39 schrieb Erich Weiler:

> Hi All,
> Forgive a probably elementary question, but I'm new to Pacemaker and am not clear on exactly how a Master/Slave relationships exist.  Here's my confusion:
> My initial though was that with a master/slave service, the service is started on both nodes (assuming I have 2 nodes).  But, I want my virtual IP to be tied to the master node only.  In my case, I have 2 nodes that have LDAP servers on them, one is the master and the other is the replicated slave.  Most of the time, I'd like the virtual IP to be tied to the master LDAP node because that one has write access for folks to change LDAP attributes like passwords and what not, but the slave is read only.  So I want the master to have the floating IP if it is alive at all times.  If the master one dies, I'd like the virtual IP to float over to the slave so folks could still access LDAP that way.  Then if the master comes back, it immediately grabs the IP back.
> However, it seems that when LDAP starts, the IP needs to be live on each node for the LDAP server to bind on that IP.  Is that how the master/slave setup works in pacemaker?  Does it use iptables or something to block the IP on the non-active node when the slave doesn't have the floating IP?
> Or maybe I'm completely misunderstanding how that works...?
> Thanks for any insight...
> -erich
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