high-availability

Muli-master OpenLDAP with 3 or more nodes

Going from a two-nodes multi-master configuration to one with more than two nodes is not really complex, once you have understood what we do in two nodes configuration :

  • In the two nodes configuration, each node has a different ServerID, in N nodes too. To let the local LDAP differentiate between the various masters, the configuration will now list a ServerID directive by node followed by the LDAP URI to connect this LDAP server.

MySQL active-passive cluster

We will use the iSCSI Lun defined in our iSCSI cluster as a shared storage and we will run MySQL in active-passive (fail-over) mode using Pacemaker and Corosync cluster engine.

The cluster will have to connect to the iSCSI target, mount the iSCSI partition on one node and start a MySQL service which has all its data on this partition.

We will need the following resources and resource agents (RA) on this cluster :

  • virtual IP → ocf:heartbeat:IPAddr2

Implementing high-availability

In the section, we will cover the technical aspects of the implementation of various solutions to create working high-available setup. This are technical howto's covering some particular aspect(s) of the software in use, to achieve a given goal.

All the pratical howto's in this section are based on the following software :
  • Distribution: CentOS 6 64 bits

  • Other repositories in use : EPEL, RPMforge