关键词: 云计算, OpenStack, 正太分布, Pull心跳模式, 累积型失效检测

Abstract: OpenStack is one of the most popular widely used open source cloud computing platforms, and it’s a required skill to achieve high availability in OpenStack. Unfortunately, due to unrealiability in hardware and software, node failure has been a major obstacle to high availability in cloud computing. In OpenStack, the failure detector is implemented by conventional heart-beat message sent by host and a timeout set to detect the failure. However, it’s unreliable because the timeout can be caused by network delay, which will affect the decision whether or not to evacuate the VMs, thus paying an unecessary and enormous price. This paper makes a research for accrual failure detector based on normal distribution of heartbeats, named P-FD. It calculates a continuous time-related value to represent the suspicion level of the monitored process. Moreover, it achieves double-check mechanism by combining pull heartbeat mode and threshold,which lowers the mistake rates. Corresponding to failure detector in OpenStack, it acts better in large-scaled and complicated cloud computing environment. The experiment shows that this failure detector greatly reduces the mistake rates and improves system availability.

Key words: Cloud Computing, OpenStack, Normal distribution, Pull Mode, Accrual Failure Detector