Live Migration of Processes Maintaining Multiple Network Connections

Single IP Address cluster offers a transparent view of a cluster of machines as if they were a single computer on the network. In such an environment, process migration can play a significant role for providing services seamlessly and for increasing sustainability. In this paper we propose a live migration mechanism which is capable of moving processes that maintain a massive amount of network connections, supporting both TCP and UDP sockets. Incoming packet loss during socket migration is prevented by exploiting the broadcast property of the Single IP Address cluster, while process live migration minimizes the execution freeze time during the actual migration of the process context. Performance evaluation on machines equipped with a 2.4GHz CPU and Gigabit Ethernet interconnect shows that migrating a process of 1GB image size and over 1000 established network connections results in less than 200ms process freeze time, rendering the transition fully transparent and responsive from the clients' point of view. The implementation is comprised entirely of a kernel module for Linux 2.6, without any changes to the existing kernel code.