|
|
In a way similar to building an HA database, you can build an HA LDAP service with clustering software as shown in Figure 15-10. Two nodes are interconnected with public networks and private networks. Private networks are dedicated to the heartbeat message. A shared disk that is connected to both nodes is used to store common directory data. Clustering software and LDAP software are installed in each node. A resource group is created, and can be failed over from one node to the other under the control of the clustering software. Instead of individual physical host IP addresses, the cluster IP address is used to access the LDAP service.
Figure 15-10 Clustered LDAP with shared disks
The cluster IP address is moved to the healthy backup node under the control of the clustering software when the primary node fails and the cluster detects the failure through the heartbeat mechanism. The LDAP client (WebSphere) uses the same IP address (the cluster IP address) to access the LDAP service, as shown in Figure 15-11. You can configure the service to fall back automatically to the primary node when the primary node is up again, or you can do it manually.
Figure 15-11 Clustered LDAP with shared disks after failover
