LDAP SDK for Java

Support for Failover and Load Balancing

The UnboundID LDAP SDK for Java provides a mechanism that can be used to manage connections across multiple servers. This can be used to provide basic support for failover and load balancing, and it can be used for single connections as well as connection pools (so a single connection pool may contain connections to multiple servers, effectively balancing the load across those servers).

The abstract ServerSet class defines the basic API used to provide this functionality. At present, the following implementations are available:

• A single server set, which contains a reference to a single server. It is primarily used for cases in which a server set may be needed, but only a single server is to be used.
  
  
• A round robin server set, in which each subsequent connection will be established to the next server in the specified list. If a given server isn't available, then it will be skipped and the server set will move to the next server in the list.
  
  
• A failover server set, in which all attempts to create a connection will be tried against the first server in the list, and will only try the second if the first is unavailable, and only try the third if both the first and second are unavailable, etc.
  
  

Additional implementations are planned for the future, and developers can create their own custom implementations as well.

Note that the failover server set can also provide failover across server sets, so it is possible to define more complex configurations (e.g., if possible, use round-robin load balancing across servers in the local data center, but if none of them are available then fail over to a round-robin set of servers in a remote data center).