Presentation on theme: "Virtualization Virtualization is the creation of substitutes for real resources – abstraction of real resources Users/Applications are typically unaware."— Presentation transcript:
1 VirtualizationVirtualization is the creation of substitutes for real resources – abstraction of real resourcesUsers/Applications are typically unaware of the substitution (layer of abstraction)Examples:computing systems/serversnetwork storage (e.g. SAN)network resources (e.g. VLANs, VPNs, HSRP - virtual ip address assignment).
2 System (machine) Virtualization A virtual machine is a tightly isolated software container that can run its own operating systems and applications as if it were a physical computer.Was first introduced by IBM in the 60’sX86 virtualization introduced in the 90’s by VMWareOn a given h/w platform (host) – simulated (virtual) machine environments are createdBenefits:consolidation to reduce hw costsworkloads consolidationsingle consolidated view/managementportability of virtual machinescan be used for testing/training
5 Virtualization approaches - Hosted Hosted approach – host O/S runs virtualization software, unmodified guest O/Ss run isolated from each other (separate virtual machines)Virtualization software is known as Type 2 hypervisorAdditional resources are required for host O/SExample: Microsoft Virtual PC, VMWare Workstation
7 Virtualization approaches - Hypervisor Hypervisor (bare-metal or type 1) approach – there’s no host O/S. Virtual machines run on top of type 1 hypervisor directly on a hardware platformNo resources are wasted for a Host O/SHigher virtualization efficiency can be achievedExample: VMWare ESX Server
9 ParavirtualizationGuest O/S is modified to include a call to hypervisor to access h/w resourcesGuest O/S is “aware” of running in a virtualized environmentMakes the structure of hypervisor simplerMay make virtual machine more efficientCan be a problem when Guest O/S can’t be modified (proprietary O/S)
11 HW VirtualizationVirtualization on x86 machines was difficult to implement, involved a lot of overheadStarting in 2005 both Intel and AMD introduced processors enabled for virtualization – Intel VT and AMD-V PacificaBoth employ virtualization extensions to x86 architecture to allow more efficient virtualization