Virtualization in HPC

Minesh JoshiCSC 469Dr. Box

Feb 1, 2012

Introduction

• HPC differ from type of server and the workloads at the workstation

• Hardware virtualization has been an important factor• Virtualization helps in advancing the power or HPC• HPC operating systems preserve the legacy compatibility• Multiple operating systems can coexist on one physical

machine• Machine is multiplexed by a small privileged kernel, known as

hypervisor or virtual machine monitor (VMM)• VMM gives illusion of one or more machines

• Coexistence of operating systems avoids incompatibilities, reduces testing and upgrade costs.

• Virtualization enables the specification of operating systems with full control over hardware resources.

• Hypervisor multiplexes the hardware resources• HPC application can bypass legacy OS mechanisms and

algorithms.• Virtual machines communicate via low-overhead and

low-latency communication mechanism

Productivity

• Hypervisor allows VM to monitor state, interrupts and communications of another VM

• Hypervisor can provide a virtual cluster of VMs• Productivity can be enhanced by using virtual

cluster• Virtual reboot avoids the latencies of hardware

re-initialization by the BIOS• Decrease the start up time for the system by

shipping VM image to all nodes in cluster

Performance

• Software pre-virtualization• Specifying memory address translations• Supports OSes Optimized for classes of HPC

applications• Hypervisor can guarantee resource allocations to a VM• Allocation of fixed percentage of CPU cycles, or

maximum latency• Interrupts handling code for a real time VM• Concurrent running of virtual cluster communicates

nodes in real time

• Focus on checkpoint/restart capability• High priority work, inter-node migration of

work in a cluster for load balancing• Preemption allows real-time HPC• These scenarios prosper the system

availability• Prevent long running HPC application loss

Security

• VM isolation provides a platform for building secure system

• Isolated VM have no unauthorized interaction• Inrospection is used to monitor the

communication and state of VM• Only trusted program loaded into an isolated

VM

Software complexity

• Hypervisor-based systems can reduce the complexity of software development

• Hypervisor should be sta• ble than usual OS• Hardware and software initialization done only

once• Maintenance of the system becomes more

automated• Gradually leads to improved software quality

Conclusion

• Virtualization helps HPC systems and applications

• Productivity, performance, reliability, availability, security, and simplicity