International Business Machines Corporation
Updating stateful system in server cluster

Abstract:

A computer-implemented method for seamlessly performing a maintenance operation on a stateful system includes mapping a network address of the stateful system to a primary server that uses a primary database to respond to incoming data requests. In response to receiving a maintenance request, the primary database is replicated to a secondary database of a secondary server. The secondary server is updated according to the maintenance request. The method further includes caching, in a replay buffer of the primary server, incoming data requests during the replicating. After the replicating, the data requests from the replay buffer are executed by the secondary server. Write operations to the primary server are disabled during the replicating, and the network address of the stateful system is mapped to the secondary server. Subsequently, the primary server is updated and reinstated by mapping the network address, and enabling the write operations.