Adaptive entitlement control of resource containers on shared servers

In this paper, we describe the design of online feedback control algorithms to dynamically adjust entitlement values for a resource container on a server shared by multiple applications. The goal is to determine the minimum level of entitlement for the container such that its hosted application achieves desired performance levels. Classic control theory is used for both model identification and controller design. Specific implementation issues that affect the closed-loop system performance are discussed. A self-tuning adaptive controller is also presented to handle limited variations in the workload. The controllers were implemented and evaluated on a testbed using the HP-UX PRM as the resource container and the Apache Web server as the hosted application in the container. In all experiments, our controller was able to quickly converge to the proper level of CPU entitlement for the Web server to track its performance target. By using our entitlement control system, shared servers can potentially reach much higher resource utilization while meeting service level objectives for the hosted applications under changing operating conditions.