Join Mike Meyers for an in-depth discussion in this video Virtualization basics, part of CompTIA Network+ (N10-006) Cert Prep: 6 Beyond the Typical Network.
- Virtualization's been around for over a decade now, but it's only been the last few years that we've really began to see people using virtualization for all kinds of stuff. If you haven't seen virtualization yet, well, let me show you one right here. So if you take a look, I am running a copy of Windows Server 2012. Well, actually that's not true. Let me show you something. What's really taking place here, is I have a copy of Windows Server, it's big screen, so it's hard to see the whole thing, but you can see I'm really running Windows 8.
And what's happening is I have a copy of Windows Server running underneath Windows 8. This is virtualization. Virtualization simply means to virtualize everything that there is about a computer into a virtual system. So when we virtualize a computer, what we're doing is we're taking all the hardware, the CPU, the RAM, everything that is this computer, and then virtualizing it within its own little system. Virtualization is important, but it's a little bit confusing for people who haven't seen it the first time.
The idea behind virtualization is that, I'm going to have some kind of host system that has real hardware, and I'm going to take that real hardware and I'm going to virtualize all that hardware, so that another virtual system within the computer can actually take advantage of it. Virtualization is a lot different than what we call emulation. For example, I love to play old Atari 2600 games. I'm sorry, I love these old, crazy games. And I can get emulators for the PC that will emulate an Atari 2600.
But trust me, there's nothing on my real, high-end laptop here that has any of the same hardware as that old Atari 2600 does. So the software pretends to be that hardware. Virtualization doesn't pretend to be anything that it's not. If you have a certain amount of RAM in this computer, your virtual machine can only take that much RAM. Whatever CPU you physically have in your computer, the virtualized CPU has to be that type of CPU. So that's a big difference between emulation versus virtualization. Now, virtualization gives us some really big benefits.
For example, we have power saving. One of the big problems we run into, particularly with servers, is that back in the old days, you'd have to have individual machines that did all the different type of server jobs. So if you had a domain controller, and then you had a web server, those were always separate machines. But they don't have to be anymore. I can take one machine. Now, this is going to be a beefy machine, don't get me wrong, it's got to have a lot of RAM in it and stuff, and I can put multiple virtual machines on that one box, and that saves us lots and lots of power.
It also gives us, as part of that, hardware consolidation. We simply don't have that many machines that we have to physically take care of. If we can consolidate all these guys onto one or two or three, whatever it is, number of boxes, we get the benefit of just not having to maintain and buy and just fix so many individual computers. The other big thing is system recovery. Now, with system recovery, the cool part about virtualization is that, when I'm running a virtual machine, when I turn that virtual machine off, it's simply saved as a file on my host computer.
So let's say I'm running my computer along, and I've got a web server that's in a virtualized machine, and it gets hacked. Well, it's really not that big of a deal with virtualization. In a virtualized world, I can just simply shut down that system, take a backup copy of the file, and fire that up, and we're up and running again. So that also helps us in terms of duplication. If, let's say, I have four or five web servers I need to build. Well, back in the old days, that would be going through the installation process, and setting up four or five physical boxes.
With virtualization, I could do one build, which is simply a file, and then drag that file over to other virtual machines and boot those up. So I could just make copies of virtual machines. Now, of course, things like software licensing and stuff like that still comes into play, but you do have that duplication option. And the last one, and the reason I love virtualization more than anything else, is research. You can only imagine how many times I get people giving me a phone call, saying, "Mike, you know, I'm running Windows XP, "Service Pack 4, and, you know, back in the old days, "did we have a Telnet "in Windows NT Version 3.51?" All these crazy questions I get.
And back not that many years ago, I used to keep all these computers around, running all these different versions of operating systems, just to be able to do R&D. Today, I've got one very, very big box, but it has a couple of hundred different setups for different operating systems in it, and if you need me to bring up a copy of Vista Home without any Service Packs, I can do it very, very quickly. So from a research standpoint, to be able to have a virtual machine that you could experiment and play with, makes it absolutely fantastic.
Anyway, what I'm going to do now is I want to play with a couple of virtual machines to give you some ideas of some of the power of virtualization. So here is my Windows 2012 virtual machine. Now, this is just the console. This is just the connection to the virtual machine. We can actually just close this, and the virtual machine will still be running. I can just close it like this. The real power to all this is what we call the hypervisor. Now, the hypervisor is the thing that manages and runs the virtual machines for us.
There are two kinds of hypervisors out here. This hypervisor, and in fact, this is what's called Hyper-V. It comes with Windows. It's really very, very powerful. And this particular tool runs on top of a host operating system. You can see I'm running Windows 8, and so this hypervisor actually runs on top of it. Now, there's another type of hypervisor. This type of hypervisor actually boots up a system. So the type of hypervisor that boots up a system, you'll see them a lot of times, these little pizza box systems.
They'll have a little USB inside the computer, it just boots off a little thumb drive. And they look something, well, I've got a picture of one. Something like this. What you're looking at here is just a console screen from VMware's ESXi hypervisor, and you literally boot from this and it just comes up. This is just one of a few basic screens that you see. OK, anyway. Back to me. So you've got two types of hypervisors.
So you've got hypervisors that run off a host operating system, or you have hypervisors that actually boot computers up themselves. So you've got two different choices there. Now, there's a lot more to virtualization, but these are the basic pieces. Make sure you understand that there are two different types of hypervisors, and also make sure you understand the benefits of virtualization.
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