AN INTRODUCTION TO SERVER VIRTUALIZATION It s green. It s flexible. It s cost effective. It s virtualization. A publication of IT Cloud design by Paul Philippe Berthelon Bravo from The Noun Project
CONTENTS: 04 Virtualization vs. Cloud Computing 05 Server Virtualization 06 Type 1 Virtualization 07 Type 2 Virtualization 08 Cost Benefits 09 Recap
INTRODUCTION: Do a lot with a little. In the world of computer technology, virtualization refers to the act of creating a virtual version of something. In recent years, virtualization has hit the spotlight due to its many applications in the corporate world. Virtualizing allows an IT infrastructure to be more efficient, have higher availability, and incur lower costs. What server virtualization boils down to is turning one computer into several; and desktop virtualization takes the load from individual workstations and transfers it to a server. All of this results in some of the most positive corporate buzzwords: consolidation, conservation, cross-platform compatibility, and improved business continuity. MEET THE AUTHOR David McClung dmcclung@excellit.com David is the Corporate Communications Coordinator at Excell IT where he manages the marketing operations and contributes to client relations activities. In addition to his marketing expertise, David enjoys dabbling in other areas of work such as graphic design, copywriting, and testing out the newest ideas in digital marketing.
Introduction to Server Virtualization Excell IT Inc. 4 VIRTUALIZATION VS. CLOUD COMPUTING Thanks to Microsoft s TV commercials, we re all familiar with to the cloud!. The world of cloud computing has flourished over the past 10 years and now encompasses the virtualization of servers, desktops, and applications. Just to be clear, virtualization are not the same thing even though the two terms are sometimes used interchangeably. Cloud computing is an umbrella term under which virtualization is just one component. Cloud computing refers to separating an application from the underlying hardware, whereas virtualization refers to the process of separating an operating system from the underlying hardware.
Introduction to Server Virtualization Excell IT Inc. 5 SERVER VIRTUALIZATION There are a couple of different ways to virtualize a server, but they always involve separating the operating system (OS) from the underlying hardware. Without virtualizing, an OS, for example Windows Server 2008, would be installed directly onto the hard drive of a server. If you were to take the hard drive out of that server and plug it into a different server, you would run into problems without doing a lengthy migration. With this traditional configuration, servers were relatively fragile. If the hard drive failed, Windows failed. If the power supply failed, Windows failed. If the memory failed, Windows failed. With virtualization, a special layer is installed in between the OS and the hardware. This layer is called a hypervisor. A hypervisor is installed onto the hardware, and then multiple instances of an operating system can be installed onto the hypervisor. These instances share the resources provided to them by the hardware (the memory, the disk space, the processing power, etc.) but are technically running off of the hypervisor. This means that if the hardware fails, the OS can continue to run if it is moved to another hypervisor on different hardware. If you have a cluster of host machines (physical servers that are running virtual servers), instances can instantly be moved from a failing host to a functional host in the cluster to avoid downtime completely! Generally, virtualized server networks involve fewer high-performance and high-cost servers running multiple instances rather than many low- to medium-cost servers with individual functions. 10
Introduction to Server Virtualization Excell IT Inc. 6 TYPE 1 HYPERVISORS There are two types of hypervisors; each with the same end-result but two different ways of achieving it. A Type 1 hypervisor, also known as a bare metal hypervisor, is the most common configuration employed in an enterprise setting. OS OS OS OS Hypervisor Physical Server While a hypervisor is a very powerful tool, it does not have an impressive graphical user interface. In fact, it barely has one at all. Once you boot up the server with a hypervisor installed, there will be a black screen with some system information on it including the IP address. With a Type 1 hypervisor, everything is managed from a management console program. This includes creating instances of operating systems, moving them, turning them on and off, and allocating physical resources to them. Some examples of Type 1 hypervisors are Oracle VM Server for SPARC, Oracle VM Server for x86, Citrix XenServer, VMware ESX/ESXi and Microsoft Hyper-V 2008/2012. 10
Introduction to Server Virtualization Excell IT Inc. 7 TYPE 2 HYPERVISORS Type 2 hypervisors differ from their Type 1 cousins in that there is another layer in the mix. With this configuration, the hypervisor is installed on a server set up with a traditional setup (the OS installed on the hardware). In this case, the hypervisor is installed just like any other program would be installed. OS OS OS OS Hypervisor OS Physical Server Since the hypervisor is not running directly off the hardware, it is not as robust of a solution as a Type 1 hypervisor because there are more possible points of failure; the OS has to boot before the hypervisor can boot, and if the OS crashes, so does the hypervisor as well as all of the instances. Allocation of resources can also pose a problem because the host OS still has requirements to run itself, but the resources allocated to the virtual machines take precedence. This means that if there are 20GB of RAM in total, the host OS requires 4GB, but the instances are using up 17GB, the host OS may crash and take everything down with it. Some examples of a Type 2 hypervisor are VMware Workstation and VirtualBox. 10
Introduction to Server Virtualization Excell IT Inc. 8 COST BENEFITS There are a few major players in the hypervisor game including Microsoft s Hyper-V, Citrix s XenServer, and VMware. From back in the day, the hypervisors are based off of a platform called Xen that was open source. Nowadays, the management console software is usually what you ll be paying for. Microsoft even bundles virtualization capabilities right in with their Windows Server 2012 operating system, allowing 2 virtual machines to be set up with just one license; this option retails for about $1700. By consolidating multiple physical servers into one virtual machine host, your energy bill can be reduced drastically. Not only that, but the total cost for the physical servers is greatly reduced despite a higher price per server. Since instances can be moved automatically and instantly between hypervisors, having a high availability cluster will also allow a company to completely avoid downtime, even in the case of a failing server. This is basically downtime insurance, so you won t have to worry about incurring data recovery costs and paying your employees to twiddle their thumbs while the network is down. Legacy applications can be kept alive in a virtual server rather than keeping a whole physical server on and running all the time just for one old program. Most of us either currently use, or know somebody who uses an ancient program from the Windows 98/XP days and that probably should have been put out to pasture long ago. Instead of keeping a whole Windows Server 2003 machine up and running, you can simply create a virtual instance of it on the same hypervisor that also powers your new and shiny Windows Server 2012 VMs! 10
Introduction to Server Virtualization Excell IT Inc. RECAP. WHAT IT DOES. No matter how you go about virtualizing your servers, there will always be a layer called a hypervisor separating the OS from the hardware, and there can be multiple instances of operating systems installed on one single hypervisor. TYPE 1 HYPERVISORS. Type 1 hypervisors are the more robust solution, with the hypervisor installed directly onto the hardware. TYPE 2 HYPERVISORS. Type 2 hypervisors are more user-friendly, but have more points of failure because the hypervisor is installed on an OS instead of directly on the hardware. IT SAVES YOU MONEY! You can accomplish the same amount of work with fewer physical servers. This brings down the cost of management, power consumption, and the total cost of hardware. TALK TO US. We have been providing businesses in the Greater Toronto Area with managed IT services for over 17 years! For assistance regarding anything in this ebook, please give us a shout at sales@excellit.com and be sure to visit www.excellit.com to learn about everything else we do!