GluStack: A Virtual Machine Cluster System with Software Assembly and Image Caching

We present GluStack, a virtual machine(VM) cluster system based on OpenStack using the KVM hypervisor and GlusterFS distributed file system. Software assembly is one of GluStack's most important features that different software chains can be based on the same base image to start different types of VM instance so as to satisfy variable working scenarios for different users easily. We also developed a new VM image format for QEMU called LBCS that implements the feature of image local block caching and sharing to achieve high I/O performance and enable instant VM startup in the GluStack architecture.