Virtualizing Observation Computing Infrastructure at Subaru Telescope

Subaru Telescope, an 8-meter class optical telescope located in Hawaii, has been using a high-availability commodity cluster as a platform for our Observation Control System (OCS). Until recently, we have followed a tried-and-tested practice of running the system under a native (Linux) OS installation with dedicated attached RAID systems and following a strict cluster deployment model to facilitate failover handling of hardware problems,(1) (2) Following the apparent benefits of virtualizing (i.e. running in Virtual Machines (VMs)) many of the non observation critical systems at the base facility, we recently began to explore the idea of migrating other parts of the observatory's computing infrastructure to virtualized systems, including the summit OCS, data analysis systems and even the front ends of various Instrument Control Systems. In this paper we describe our experience with the initial migration of the Observation Control System to virtual machines running on the cluster and using a new generation tool ansible to automate installation and deployment. This change has significant impacts for ease of cluster maintenance, upgrades, snapshots/backups, risk-management, availability, performance, cost-savings and energy use. In this paper we discuss some of the trade-offs involved in this virtualization and some of the impacts for the above-mentioned areas, as well as the specific techniques we are using to accomplish the changeover, simplify installation and reduce management complexity.