When configured with an LDAP external server template, either the fewest operations algorithm or the failover load-balancing algorithm will use the topology registry to determine which Directory Server instances should be accessible through the server. To accomplish this, the load-balancing algorithm searches for directory-server-instance objects with a load-balancing-algorithm-name property that matches the name of the load-balancing algorithm. For example, in the following sample configuration, the load-balancing algorithms are named dc_example_dc_com-fewest-operations and dc_example_dc_com-failover, so if you want a Directory Server instance to be accessible through those load-balancing algorithms, add those values to the load-balancing-algorithm-name property in the topology registry’s entry for that instance. You can do this with a configuration change similar to the following:
dsconfig set-server-instance-prop \
     --instance-name ds1.example.com:636 \
     --add load-balancing-algorithm-name:dc_example_dc_com-fewest-operations \
     --add load-balancing-algorithm-name:dc_example_dc_com-failover
The PingDirectoryProxy Server automatically detects and reacts to applicable changes in the topology registry. This includes the following::
  • Adding a new Directory Server instance to the topology. If this instance has any load-balancing-algorithm-name values that match the names of any load-balancing algorithms that are configured for automatic backend server discovery, the new instance is immediately eligible to process client requests (as soon as the instanced satisfies all of the configured health checks).
  • Removing an existing Directory Server instance. If this instance had been associated with any load-balancing algorithms, then it is no longer eligible to receive requests through these load-balancing algorithms.
  • Modifying an existing Directory Server instance to add one or more values to the load-balancing-algorithm-name property. If any of the new values matches the name of any of the configured load-balancing algorithms, the instance is immediately eligible to process client requests.
  • Modifying an existing Directory Server instance to remove one or more values from the load-balancing-algorithm-name property. If any of the removed values matches the name of any of the configured load-balancing algorithms, then the instance is no longer eligible to receive requests through these load-balancing algorithms.