Reducing VM Startup Time and Storage Costs by VM Image Content Consolidation

摘要

Elastic cloud applications rely on fast virtual machine (VM) startup, e.g. when scaling out for handling increased workload. While there have been recent studies into the VM startup time in clouds, the effects of the VM image (VMI) disk size and its contents are little understood. To fill this gap, we present a detailed study of these factors on Amazon EC2. Based on our findings, we developed a novel approach for consolidating size and contents of VMIs. We then evaluated our approach with the ConPaaS VMI, an open-source Platform-as-a-Service runtime. Compared to an unmodified ConPaaS VMI, our approach results in up to four times reduction of the disk size, three times speedup for the VM startup time, and three times reduction of storage cost.