Platform/Server Virtualization Flashcards (Lec 8)

Flashcards about Platform/Server Virtualization

Virtualization

The term used when something is spoofed or faked in IT, especially in system or server contexts.

System Virtualization

The process of emulating hardware so it can be made available to multiple logical systems.

Benefit of System Virtualization

The ability to run multiple operating systems simultaneously on a single computer.

Virtual Server

A single computer that appears as independent computers to multiple client or guest operating systems.

Traditional Hardware Setup

Hardware is dedicated to an OS, on which applications run.

Virtualized Hardware Setup

Virtualization software emulates hardware, which guest OSes use as if real.

IBM VM/370

Virtual Machine facility, started by IBM in the 1960s to partition large mainframe-based systems.

Reason for Virtualization Abandonment in 1980-1990

Due to inexpensive x86 servers and the popularity of client/server applications

VMware

Company that started virtualization support for x86 systems in 1998.

Problem Addressed by VMware

Server bloat, low utilization, high infrastructure cost, high management/maintenance cost, poor disaster recovery/failover protection.

Client Based (Hosted) Architecture

Virtualization layer installed on top of an existing Operating System as an application.

Workstation Virtualization

Another name for Client Based (Hosted) Architecture.

Advantage of Client Based Architecture

Best support for host hardware (sound cards, USB ports, etc.).

Bare-Metal (Hypervisor) Architecture

Virtualization layer is installed directly on the hardware; no separate Operating System is necessary.

Advantage of Bare-Metal Architecture

More efficient than hosted architectures.

Virtual Machine (VM)

Each environment available for OS installation.

Guest Operating System

The operating system installed in a VM.

Host Operating System

In a hosted architecture, the O/S in which the virtualization software runs.

Hypervisor

The software that provides the virtualization layer in a bare-metal architecture.

Virtualization Advantage: Flexibility

Can run different types of O/Ses on same hardware.

Virtualization Advantage: Cloning

Virtual machines can be easily cloned or used as templates.

Virtualization Advantage: Portability

Virtual machines can be quickly moved among servers.

Virtualization Advantage: Test Environments

Can quickly create test environments.

Virtualization Advantage: Reliability

A virtual machine can be configured to automatically move from a failed server to one that is still working.

Fail-Over

A virtual machine configured to automatically move from a failed server to one that is still working

Advantage: Consistent Hardware Interface

Provides a consistent hardware interface regardless of the underlying physical hardware.

Advantage: OS Compatibility

Can run an O/S on hardware not natively supported.

Virtual Appliance

An entire installation, including the O/S, can be added to a virtual machine server.

Advantage: Increased Capacity and Scalability

Virtual members of a cluster can spin up or down as needed to meet current demand.

Cloud Computing

Virtual members of a cluster can spin up or down as needed to meet current demand.

Advantage: Lower Infrastructure Costs

Includes saves physical or rack space, less hardware to maintain, increased hardware utilization

Advantage: Reduced Energy Costs

Includes less power consumption and less cooling.

Virtual Machine Single Point of Failure

If the host OS or hardware crashes, all VMs crash.

Disadvantage: Complicates hardware maintenance

If you need to take the host server down multiple guests are affected.

Disadvantage: Tracking Software and OSes

Harder to keep track of software and OSes.

CPU Virtualization

Virtualization of the proccessing unit to enable multiple VMs

Full Virtualization

Uses binary translation to execute instructions that are non-virtualizable.

Advantage of Full Virtualization

Offers the best isolation and most security between VMs.

Paravirtualization

Uses a modified guest OS to remove non-virtualizable instructions.

Paravirtualization nickname

OS Assist, uses a modified guest OS to remove non-virtualizable instructions.

Advantage of Paravirtualization

Good performance due to use of modified OS

Hardware Assisted Virtualizaiton

Hypervisor traps non-virtualizable instructions and re-issues them to hardware in root mode.

Advantage of Hardware Assisted Virtualization

Compatibility is excellent due to function of CPU enhancements.

Memory Virtualization

Uses virtual to physical mappings maintained by the hypervisor.

Memory Virtualization Implementation

Each VM 'thinks' it has contiguous memory space available

Effect of Memory Virtualization

Standard libraries can be shared among VMs reducing required memory.

Device and I/O Virtualization

Involves managing the routing of I/O requests between virtual devices and the shared physical hardware.

Performance Drawback of Device and I/O Virtualization

Biggest performance hit in system virtualization.

Future of Virtualization

Virtualization will continue to be a key technology through the foreseeable future.

Virtualization Software Future Development

Remove the requirement to do binary translations, not require specially-configured guest Oses, remove the performance hit incurred by using Hardware Assisted technologies

Client Based Virtualization Software: Windows

VMware Player/Workstation/Server, Microsoft VirtualPC, Bochs, VirtualBox

Client Based Virtualization Software: Macintosh

Parallels, VMware Fusion

Client Based Virtualization Software: Linux

OpenVZ, VirtualBox, Bochs, KVM (Kernel Virtual Mode)

VMware vSphere

Represents an entire suite of virtualization products.

ESXi Server

Virtualization software being used in lab

Microsoft HyperV

Hypervisor virtualization software used by Windows clients

Xen

Hypervisor virtualization software used by Amazon/Rackspace/etc. Cloud backend

Virtual memory

Memory that appears to exist but is not physically present, allowing programs to address more memory than is physically available.

Virtual drives

Storage space that appears to be a physical hard drive but is actually a file or a portion of a physical drive.

Virtual CD-ROMs

Emulated CD-ROM drives that allow access to disc images without requiring a physical drive.

Emulation

The process of mimicking the behavior of one system on a different system, allowing software designed for one environment to run on another.

Spoofing

The act of disguising the identity of a system or user to gain unauthorized access or deceive other systems.

Paravirtualization Compatibility

Generally has poor compatibility due to requiring a modified guest OS.

Hardware-assisted virtualization Performance

Offers excellent compatibility but may result in lower performance compared to other virtualization methods.

Binary Translation

A technique used in full virtualization to convert non-virtualizable instructions into virtualizable ones.

Virtual switch

A software-based switch that allows virtual machines to communicate with each other and with the external network.

Virtual network adapter

A software-based network interface card that allows a virtual machine to connect to a virtual network.

Snapshot

A point-in-time copy of a virtual machine's disk and memory state, allowing it to be reverted to a previous state.

Template

A pre-configured virtual machine that can be used as a base for creating new virtual machines.

Live Migration

The process of moving a running virtual machine from one physical server to another without interrupting its operation.

Thin Provisioning

A storage allocation technique where storage space is allocated on demand, rather than pre-allocated in advance.

Thick Provisioning

A storage allocation technique where storage space is pre-allocated in advance, regardless of actual usage.

Virtual SAN

A virtual storage area network that provides shared storage resources to virtual machines.

Resource Pooling

The aggregation of physical resources into a shared pool that can be dynamically allocated to virtual machines.

Orchestration

Automated arrangement, coordination, and management of computer systems, applications, and services

Windows Virtual PC

A virtualization program by Microsoft, primarily designed to run older operating systems on newer versions of Windows.

OpenVZ

A container-based virtualization platform for Linux.

KVM (Kernel Virtual Machine)

A full virtualization solution for Linux systems.

Parallels Desktop

A virtualization software for macOS providing the ability to run Windows, Linux, and other operating systems.

Memory ballooning

A technique used by hypervisors to reclaim unused memory from virtual machines.

Virtual TPM

A software-based Trusted Platform Module for virtual machines.

Hot Add

The ability to add virtual hardware resources to a running virtual machine without requiring a reboot.

Nested Virtualization

Running a hypervisor inside of a virtual machine.

Virtualization security

The methods, techniques, and controls used to protect virtualized environments from threats.

VM sprawl

The uncontrolled growth of virtual machines, leading to management and resource utilization challenges.