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Server virtualization. OUTLINE . Introduction Virtual Machine Virtualization Server Virtualiztion. Introduction. VMM(hypervisor): a software abstraction layer between hardware and the OS and applications running on top of it. VMM directly control hardware resource.
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OUTLINE • Introduction • Virtual Machine • Virtualization • Server Virtualiztion
Introduction • VMM(hypervisor): a software abstraction layer between hardware and the OS and applications running on top of it. VMM directly control hardware resource. • Virtualization first developed in 1960’s to partition large mainframe computer into several logical instances to run on single physical mainframe hardware as the host.
Virtual Machine • Virtual Machine: is an abstract layer between hardware and end-user (sometimes referred as virtual server). Virtual machines run OS. A host OS can run many virtual machine and share system hardware components such as CPUs, disk, memory, I/O among virtual servers.
Virtual Machine • Virtual Machine Types: • Software virtual machine (Microsoft Virtual Server 2005):
Virtual Machine • Hardware virtual machine (VMWare ESX):
Virtual Machine • Virtual O/S container: host OS is partitioned into containers or zones (Solaris Zones, BSD Jail). Each zone has its own unique process table and management tools.
Virtualization Virtualization allows a single computer to host multiple virtual machines, each isolated from one another, with the possibility of running different OS.
Virtualiztion • Advantages: • Multiple execution environment. • Virtual hardware • Multiple simultaneous OS. • Better use of existing hardware • Disadvantages: • Decrease performance. • Management Interface because of several platforms into the same environment. • Increase Network complexity and Debugging time.
Server (machine, cpu) Virtualization • Is a type of virtualization (besides, Desktop virtualization, Application virtualization (portable version)…) • The ability to run an entire virtual machine, including its own OS on another OS.
Server virtualization • Server virtualization types: • Traditional architecture:
Server virtualization • Emulation: a complete hardware architecture is created in software. • The guest OS not have to be modified to run on host architecture. • Drawback: each instruction on the guest system must be translated to be understood by the host system.
Server virtualization • Binary translation: the hypervisor manages the access of each guest OS to the physical hardware resources.
Server virtualization • Hosted OS, application – layer abstraction virtualization: resides as an application on top of underlying OS.
Server virtualization • Hardware- assisted virtualization (full virtualization, bare-metal virtualization)
Server virtualization • VMM is directly supported by host hardware. (compared to binary translation)
Server virtualization • Paravirtualization:
Server virtualization • Guest OS includes modified(paravirtualized) I/O drivers for the hardware. No need hypervisor instead the guest OS makes call directly to the virtualized I/O services and other operations.
Server virtualiztion • Hosted OS, kernel-layer abstraction (OS Containers virtualization, Single Kernel Image (SKI))
Server virtualization • No need hypervisor. Use containers, or sandboxes, called chroot, to partition the • host operating system into containers or zones (e.g. • Greater performance than binary translation • Potential of conflict between multiple virtual machines.
References • Server virtualization technology and its latest trends (Yoshihiko Oguchi and Tetsu Yamamoto) • Survey of Server virtualization (Radhwan Y Ameen and Asmaa Y. Hano)