Virtualization B Ramamurthy References Practical Virtualization Solutions Virtualization

Virtualization B. Ramamurthy

References • Practical Virtualization Solutions: Virtualization from the Trenches by K. Hess and A. Newman, Prentice-Hall Inc. , 2009, ISBN 13: 978 -0 -13714297 -2. • P. Li. Selecting and using virtualization solutions – our experiences with VMware and Virtualbox, CCSC 2009, vol. 25, no. 3, Jan 2010, pp. 11 -17.

Moore’s law • Intel co-founder Gordon Moore is a visionary. His prediction, popularly known as Moore's Law, states that the number of transistors on a chip will double about every two years. Intel and other semiconductor companies kept that pace for over 40 years. • GPU’s performance and functionality have been increasing at a faster pace than Moore’s law.

Recent Advances • Multi-core: how to fully harness the power of multi-core? Intel has been trying really hard to make us all program for multi-core!!! • Large scale data: How to manage large scale data? Google, Yahoo, NSF and CRA have been promoting their file systems and Map. Reduce!! • Parallel processing of data: How to configure clusters to process data in parallel? • Answer: Virtualization?

Virtualization • Virtualization is creation of an alternative to actual version of something: ▫ virtual memory (more memory than physically available), ▫ virtual time (buffering provides virtual/effective download time that less than the actual time), ▫ Virtual hardware, desktop, disk, appliances, scenes, ▫ Virtual worlds • In our context it is realizing one or more complete computer systems as guests on the base machine/operating system. • This offers an excellent conduit for delivering the vastly underutilized power of the multi-core and other resources such as storage and devices.

Early days of VM • Technology was initially popularized in 1960’s by IBM. • IBM 370 /VM • 1990 VMware released its virtualization product: slow, based on x 86 platform (no multi-core), expensive • Now, we have ▫ ▫ ▫ ▫ VMware suite; MS virtual PC, Hypervisor; QEMU (Quick Emulator): open source XEN Open. VZ KVM Virtual. Box

Types of Virtualization • Bare metal virtualization (Hypervisor? ): A system is installed directly on the hardware rather than on the host operating system ▫ Difficult parts of the underlying hardware need not be virtualized • Paravirtualization: is a virtualization technique that presents a software interface to virtual machines that is similar but not identical to that of the underlying hardware: VMware, XEN ▫ A hypervisor as a privileged level accessing the hardware ▫ On top of the hypervisor is the guest system • Hardware-Assisted Virtualization (HVM): Zen-HVM allows interaction between paravirtualized system and the hypervisor

Host. OS/Guest. OS Products • VMware server: introductory package for small environments: limited use in large environments • Sun(now Oracle) x. VM or Virtual Box: favorite among academicians as well as the authors of this text. Adjustable video memory, remote device connectivity, RDP connectivity, snappy performance, may be best hosted virtualization package.

Hypervisor Products • Hypervisor: Hypervisor is a bare metal approach; is installed on the bare metal and then the operating systems is installed (paravirtualized); the operating system is designed as VM zero. ▫ Ex: VMware ESXi: 32 MB footprint! ▫ Hardware is virtualization optimized ▫ VM management via Direct Console User Interface (DCUI) at the physical console of the server system ▫ Vmkernel allows for remote mangement vis a set of APIs and agents.

Hypervisor-based Products • Citrix Xen: Earlier versions (<=3. 0) were very slow. >4. 0 version is very fast and the speciality is the template engine, high end virtualization • VMware ESX/ESXi: enterprise virtualization at its best. Free product • Microsoft Hyper-V: above products are Linux based and MS came up with Windows server version of virtualization in this product.

Emulation-based Products • Emulation refers to the capability to mimic a particular type of hardware for an operating system regardless of the underlying host operating systems. • Ex: Sparc version of Solaris on a non-Sparc machine. • Slow; • Examples: Bochs, QEMU, MS Virtual PC and Virtual Server • Bochs is a free, open source Intel architecture x 86 b (32 bit) emulator that runs on Unix, Linux, Windows, and Mac OS • QEMU is another free, open source emulation program that runs on limited number of host archs. : x 86, Sparcx, MIPS, Power. PC, m 68 K guest OS.

Emulation Products (contd. ) • MS Virtual PC is a software package from Microsoft. • For windows env. These are good products.

Kernel-level Virtualization • Multiple root systems • VM uses its own kernel to boot the guest VM (called root file system) • Examples: KVM (Kernel Virtual Machine): modified QEMU but uses virtualization processor extension • User Mode Linux (UML) uses an executable kernel and a root file system to create a VM. UML is a part of Linux after 2. 6. x kernels!

Shared kernel • Is also called Operating system virtualization or system level virtualization, takes advantage of the unique ability of Unix and Linux to share kernel with other processes in the system. • chroot is the command typically used • Container-based virtualization • Examples: Solaris container zones, • Open. VZ

Recommendation ▫ ▫ Xen VMware ESX MS Virtual PC (for Windows env. ) For us: VMware server and Sun’s Virtual box Finally, there are other products besides these and many more to appear esp. with the explosion of cloud computing.