Cheat Sheet

Virtualization For Dummies

From Virtualization For Dummies by Bernard Golden

Virtualization saves money, energy, and space. After you’ve decided to go virtual, take steps to make implementation easier: Get to know some important terms about virtualization, types of virtualization, and leading companies and products in virtualization.

Reasons for Moving to Virtualization

If you’re trying to decide if virtualization is right for your organization, whether from an economic or technological standpoint, consider these reasons for taking the virtualization plunge:

  • It saves money: Virtualization reduces the number of servers you have to run, which means savings on hardware costs and also on the total amount of energy needed to run hardware and provide cooling.

  • It’s good for the environment: Virtualization is a green technology through and through. Energy savings brought on by widespread adoption of virtualization technologies would negate the need to build so many power plants and would thus conserve our earth’s energy resources.

  • It reduces system administration work: With virtualization in place, system administrators would not have to support so many machines and could then move from firefighting to more strategic administration tasks.

  • It gets better use from hardware: Virtualization enables higher utilization rates of hardware because each server supports enough virtual machines to increase its utilization from the typical 15% to as much as 80%.

  • It makes software installation easier: With software vendors tending more and more towards delivering their products preinstalled in virtual machines (also known as virtual appliances), much of the traditional installation and configuration work associated with software will disappear.

Types of Virtualization

Currently, most of the activity in the virtualization world focuses on server virtualization —– the data centers or server farms. The three main types of server virtualization are:

  • Operating system virtualization (aka containers): Creates self-contained representations of underlying operating system in order to provide applications in isolated execution environments. Each self-contained environment (container) reflects the underlying operating system version and patch level.

  • Hardware emulation: Represents a computer hardware environment in software so that multiple operating systems can be installed on a single computer.

  • Paravirtualization: A thin software layer that coordinates access from multiple operating systems to underlying hardware.

Major Players and Products in Virtualization

Once you’ve decided on switching to a virtualized environment, where do you go for solutions, support and products? This list represents the major players in virtualization:

  • VMware: The big daddy of the field. Provides hardware emulation virtualization products called VMware Server and ESX Server.

  • Xen: A new open source contender. Provides a paravirtualization solution. Xen comes bundled with most Linux distributions.

  • XenSource: The commercial sponsor of Xen. Provides products that are commercial extensions of Xen focused on Windows virtualization. XenSource was recently acquired by Citrix.

  • OpenVZ: An open source product providing operating system virtualization. Available for both Windows and Linux

  • SWsoft: The commercial sponsor of OpenVZ. Provides commercial version of OpenVZ called Virtuozzo.

  • OpenSolaris: The open source version of Sun’s Solaris operating system provides operating system virtualization and will also provide Xen support in an upcoming release.

Virtualization Project Steps

After you’ve evaluated virtualization and want to move forward with it, it’s time to implement a virtualization plan. Don’t jump right in, the first steps are to create a virtualization project using these five steps:

  1. Evaluate your current server workloads.

    Determine whether virtualization can help you and figure out what your potential virtualization use cases might be.

  2. Define your system architecture.

    What form of virtualization will you use, and what kind of use case do you need to support?

  3. Select your virtualization software and hosting hardware.

    Carefully evaluate the virtualization software’s capabilities to ensure that it supports your use cases. Be sure to look at the new virtualization-enabled hardware systems.

  4. Migrate your existing servers to the new virtualization environment.

    Decide whether some of the new migration products can help you move your systems or if you need to move them manually — in either case, create a project plan to ensure everything is covered

  5. Administer your virtualized environment.

    Decide whether the virtualization product management tools are sufficient for your needs or whether you should look to more general system management tools to monitor your environment.

Virtualization Mini-Glossary

To help you get a better understanding and expand your knowledge of virtualization, get to know these useful terms and how they apply to virtualization and its process:

Bare metal: Virtualized servers in which the virtualization software is installed directly on the machine rather than on an operating system. Because it installs on the machine, it is said to reside on “bare metal.”

Client virtualization: Using virtualization to enable a client device (like a laptop) to support isolated operating environments. Client virtualization is often used to move workloads into isolated environments to reduce system administration requirements.

P2V: Shorthand for “physical to virtual.” P2V stands for the process of migrating systems from the physical hardware they originally ran on to virtual operating environments running in a virtualized environment.

Server virtualization: Running virtualization software on server machines in order to host multiple operating system environments on a single piece of hardware.

Storage virtualization: Using shared storage located on individual servers so that multiple servers can share a single storage device. Storage virtualization is often implemented after initial server virtualization efforts in order to centralize resources and reduce storage administration work.

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