New Age Vertualization

We take a look at the key trends in virtualization, reasons to embrace the technology and some hot new technologies that are coming up. Also for those who're not satisfied by tech-talk alone, we 'll talk about how to migrate different types of virtual appliances from one virtualization platform to another

Wednesday, May 07, 2008

Virtualization is nothing new, this term has been known since the early 1960s, but the concept, usages, and the benefits have changed monumentally in last few years. Not so long back, virtualization was supposed to be only a good platform for developers who used to do multi-platform software testing. Owing to its feature that multiple OSs could run on top of one single hardware box, it used to solve this purpose very nicely. But at that time it was mostly not considered to be reliable enough for production environments. The main reasons for this were the single point failure which it used to create for the production machines, plus the resource consciousness was also not that great. The virtualization layer sitting between the host and guest OS used to eat up a lot of resources.

But today the whole story has changed. The growing density of datacenters has made the CIOs think for the alternatives that can save power, equipment, and most importantly the real state. And the only way to achieve this is by doing server consolidation. Today virtualization is one of the biggest enabler for consolidation. So what about the issues with resource allocation and single point of failure which virtualization was prone to? Ok, the answer to this is very simple. First of all, if you are yet not aware then let me introduce you to the term hypervisor. This is one technology which had improved the resource allocation in virtualization tremendously and had made it robust enough to handle enterprise class, mission critical production servers. We will look into its technicalities and how it works, following in this story. Plus with the advent of concepts like virtual appliances the difficulty of deploying applications has become so negligible that today the IT managers just love this concept. We will also delve into this concept in detail.

And to answer the second part of the question, let's take an example. Assume that you have four different services running on four different hardware server boxes. Now if you want to migrate all those physical servers into one single physical server by using virtualization, and your concern is that, if that particulate single machine fails then all of your four services will come to a stop. Now, to answer this, the possibility of any kind of a hardware failure is equal in all the four servers which you were running and ideally you should have kept backups for all those four servers. But now as you have migrated your serviced to a virtual environment, hence as a result you have only one server and you can keep a backup of just that. So now instead of having a one on one fail safe for your four servers for which you had to buy eight hardware server boxes now you have to buy just two. Isn't that better in terms of the TCO of your datacenter?

Now you might say that the servers which can take four such virtual machines would be radically expensive. But believe me it's not the case. Around one year back when we did the server shootout in our labs we have seen server with dual quad core processors and around 16GB of RAM for less than a Lakh http://pcquest.ciol .com/content/pcshootout/2007/1107081001.asp. And those servers were capable enough to generate a whopping 50Gigaflops of processing which is half the performance of Param 10000 (The super computer from CDAC build in 1995).
Now with that note, let's take a closer look to the two great virtualization technologies of today, the hypervisor and the Virtual Appliances.

From this screen of WinImage you can select the type Virtual Disk you want to create from your physical machine. It can be either Dynamic or Fixed	To convert a remote physical machine to a vmdk image all you have to do is to provide the IP address of the machine and continue the wizard

The Hypervisors
The concept of hypervisor for commodity servers and desktops started with two things, the XEN, which was one of the pioneers to bring full virtualization in commodity servers and desktops. And the second was the hardware virtualization initiative from chip manufacturers like Intel and AMD. Intel's VT and AMD's V or Pacifica is the technologies which let hypervisors run directly on top of the hardware natively using the processors. A hypervisor is a technique to run virtualization in full-virtualization mode, which means a setup where the virtualization layer essentially runs on top of the hardware and below the Operating System. You will know the difference by comparing it with any traditional virtualization system, where the virtualization layer runs on top of the host OS. The hypervisor runs directly on top of the hardware, and uses the virtualization features of the underlying CPU, eg. Intel's VT and AMD's Pacifica.

As the virtualization layer sits directly on top of the hardware, it is very thin and lightweight. It is also more resource conscious. Both of these features make its performance much better as compared to traditional virtualization techniques. And hence it becomes ready for mission critical applications.

Virtual Appliances
Virtual Appliances are a preinstalled and configured harddisk image of a virtualized application with some specific feature. So for instance, PCQLinux ERP and CRM appliance is a VirtualBox-based hard disk image of a preinstalled Linux distro with TinyERP preconfigured in it. All you have to do to run it is to copy the harddisk image to a machine with virtualbox and run it. No need to install, update, or configure anything.

Virtual Appliances are a boon for IT Managers, with the help of such appliances the deployment of software and service has become dramatically easy. These appliances are becoming most favored mode of software delivery for IT managers and developers. We talked about Virtual Appliances many times and our PCQLinux 2008 distribution is also based on the same lines. But still if you are new to this concept then you can read the story called Applications as appliances in the JAN 2007 issue of PCQuest or you can visit the website http://pcquest.ciol.com /content/depth/2007/107010101.asp.

To convert a VPC appliance to VMWare appliance you can use the VMWare Converter. Just select the third option in the Import wizard and proceed	You can even natively run your VPC appliance in VMWare Workstation and Player

And the other great thing about such appliances is that there is a Varity of such free and opensource appliances available out there over the net. So just name an open source application and you will find it in a preconfigured appliance format. All you have to do is to download and boot it. But there is a catch, if you have ever tried finding any appliance over the internet more than ones, I am sure most of you had faced a very common problem. The appliance is available but not for the virtual environment you want it for. So let's say you have a production environment where you are using Microsoft Virtual Server and suddenly you tried to search for an appliance for let's say Comp i.e ERP, you might find it but for may be VMWare or for XEN. And hence interop had become the need of the day, so that by any means you can convert that appliance to run on your environment and not the other way round where you have to deploy a new environment just to run an appliance which is actually not feasible for production environments. But believe me it might sound impossible or difficult for most of you, but today it's very much possible to interoperate between different virtual environments in terms of appliances. Which means either you can run any appliance created for let's say x virtual environment on y virtual environment natively or you can first convert it and then run it. And so is for physical to virtual. We will take a more hands on look into this topic but before that, let's take a close look on the new kid in the block which is catching a lot of eyes now a days. And that is the MS HyperV.

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