This procedure describes how to configure the directory service load balancer (ds.pstest.com at IP address 10.0.2.10). The steps are relatively generic; the details depend on the load balancer you are using.
Populate the load balancer's Hosts Table.
Add the IP address for ds1.pstest.com and ds2.pstest.com to the load balancer's hosts table.
Populate the load balancer's Real Service Table.
Add the real services for ds1.pstest.com and ds2.pstest.com. A real service is identified by its IP address and port. Add 10.0.1.1:389 and 10.0.1.2:389.
Populate the load balancer's Service Group Table
Add the service group for directory services. The service groups are sets of the real services that you defined in Step 2. The real services in the group must be capable of fulfilling the same type of request. The load balancer will distribute requests among the real services in the service group. When you define the service group for ds.pstest.com, you add the real services that specify the Directory Server instances, 10.0.1.1:389 and 10.0.1.2:389.
Populate the load balancer's Virtual IP Table.
A virtual service definition includes the outward facing IP address and the port at which the load balancer accepts requests for a service, as well as the service group that you specified in Step 3, which actually handles the requests. The load balancer will accept requests at the virtual service address and distribute them among the service group. The virtual service definition for the directory service should be ds.pstest.com, with the virtual IP address of 10.0.2.10:389, and with the service group consisting of the computers ds1.pstest.com and ds2.pstest.com.
Configure the load balancer to use Layer-4 (TCP layer) load balancing.
If you are using a load balancer that supports long, persistent TCP connections, this is the best option. There is no need for stickiness at the directory service load balancer because the TCP connections remain open.
Configure the load balancer with a scheduling type of either least connections or round robin.
Both scheduling types initially distribute the connections evenly between the Directory Server instances. Both scheduling types keep connections evenly distributed if the connections are restarted.
Configure the health-check settings for the load balancer.
The recommended settings are specified in Table 3–5.