Dynamic load balancing of SSH sessions using user-specific selection policies

Ballast is a tool for balancing user load across SSH servers based on various criteria such as CPU load and system availability. It includes a load balancing client, a lightweight data server, and a data collection agent. Ballast is invoked as part of the SSH login process, so has access to the user name while making balancing decisions, which is not available in traditional load balancing approaches. This gives Ballast the unique ability to perform user-specific load balancing. This paper presents the Ballast architecture and examines the benefits of involving user-specific criteria in the balancing process. Two approaches for utilizing user information based on prediction and dynamic load metrics are analyzed using trace-based simulation and are found to have significant benefits when combined.