Controlling access of clients to service in cluster environment

A computer-readable medium having computer-readable instructions stored thereon that, when executed by a processor, cause the processor to perform a method for controlling access of a plurality of clients to a service, the service provided by each of a plurality of servers, the method comprising:

• creating a first set of addresses, a second set of addresses, and a third set of addresses, where the first set of addresses comprises addresses that are registered in a name server, the second set of addresses comprises addresses that are not registered in the name server, the third set of addresses comprises addresses not registered in the name server, and the second and the third sets of addresses are disjoint;
• determining a first server of the servers as a server that has failed and to which the access is to be prohibited, the first server being associated with a first address of the first set of addresses;
• moving the first address from the first set of addresses to the third set of addresses;
• removing the first address from the first server and assigning the first address to a second server of the servers;
• and
• removing the first address from the name server.

An apparatus comprising:

• networking hardware to operably couple to a name server;
• a processor;
• and
• a computer-readable data storage medium storing processor-executable instructions performable by the processor to:
• create a first set of addresses, a second set of addresses, and a third set of addresses, the first set comprising addresses registered in the name server, each of the second set and the third set comprising addresses not registered in the name server, and the second and the third sets of addresses being disjoint;
• move a first address of a first server that has failed and to which access is to be prohibited from the first set to the third set, remove the first address from the first server and assign the first address to a second server, and remove the first address from the name server;
• in response to a condition being satisfied, remove the first address from the second server, and move the first address from the third set to the second set;
• upon which the access to the server no longer being prohibited, assign a second address of the second set to the first set, and add the second address to the name server.