1. A computer system comprising: a first instance of a cluster to process a first plurality of service requests; a second instance of the cluster to process a second plurality of service requests; a dispatcher to route the first plurality of service requests to the first instance and the second plurality of service requests to the second instance of the cluster; a patch tool to initiate an upgrade of a plurality of software components running on the cluster instances, the upgrade is performed in rolling mode with zero downtime for the cluster; and a public store to store an execution code and related data for the plurality of software components running on the cluster instances, the related data comprising one of a state of execution and application data.