Virtualization technology is widely used in cloud data centers and today’s IT infrastructure. A key technology for server virtualization is the live migration of virtual machines (VMs). This technology allows VMs to be moved from one physical host to another while minimizing service downtime. The cloud providers usually use cloud operating system for virtual machine management. Currently the most widely used open source cloud operating system is OpenStack. In this paper, we investigate the reliability of VM live migration in OpenStack by increasing the system pressures and injecting network failures during the migration. We analyze the impact of these pressures and failures on the performance of VM live migration. The experimental results can be used to guide data center administrators in migration decisions and fault localization. Furthermore, it can help researchers to find bottlenecks and optimization methods for live migration in OpenStack.