Fast and Scalable VMM Live Upgrade in Large Cloud Infrastructure Xiantao Zhang Xiao Zheng Zhi Wang Alibaba Group Alibaba Group Florida State University
[email protected] [email protected] [email protected] Qi Li Junkang Fu Yang Zhang Tsinghua University Alibaba Group Alibaba Group
[email protected] [email protected] [email protected] Yibin Shen Alibaba Group
[email protected] Abstract hand over passthrough devices to the new KVM instance High availability is the most important and challenging prob- without losing any ongoing (DMA) operations. Our evalua- lem for cloud providers. However, virtual machine mon- tion shows that Orthus can reduce the total migration time itor (VMM), a crucial component of the cloud infrastruc- and downtime by more than 99% and 90%, respectively. We ture, has to be frequently updated and restarted to add secu- have deployed Orthus in one of the largest cloud infrastruc- rity patches and new features, undermining high availabil- tures for a long time. It has become the most effective and ity. There are two existing live update methods to improve indispensable tool in our daily maintenance of hundreds of the cloud availability: kernel live patching and Virtual Ma- thousands of servers and millions of VMs. chine (VM) live migration. However, they both have serious CCS Concepts • Security and privacy → Virtualization drawbacks that impair their usefulness in the large cloud and security; • Computer systems organization → Avail- infrastructure: kernel live patching cannot handle complex ability. changes (e.g., changes to persistent data structures); and VM live migration may incur unacceptably long delays when Keywords virtualization; live upgrade; cloud infrastructure migrating millions of VMs in the whole cloud, for example, ACM Reference Format: to deploy urgent security patches.