Virtualization How-To Part 2

The second problem most companies experience (including my first IT Job) is the updates that need to be performed to all desktop images on a daily, weekly and monthly basis. You have the Microsoft patches, the anti-virus patches, the application patches or updates and the list just goes on and on. Although they seem simple enough, patches and updates for a desktop image can have devastating consequences for a company when deployed incorrectly. Remember Joe down in IT from my previous postings? He cost the company thousands of dollars simply by pushing out a Microsoft patch that wreaked havoc on the environment. The answer? Citrix XenDesktop with Citrix Provisioning Services.

Citrix Provisioning Services allows you to take one “golden desktop image” and publish it to entire user communities quickly and efficiently. How is this any different from desktop PC imaging software like Ghost you may ask? Well once you have this image, you can update the image live and publish it out to your users without significant interruptions. The next time the user logs off and logs back in, they will receive the updated image quickly (unlike a 20 minute image process per PC). Problems with the image like Joe from IT had? Just a couple of clicks and your users are back on the image that was previously working for them.

So Provisioning Services is great if you have a bunch of physical PCs that you need to manage and don’t want the hassle of other imaging technologies, but what about using it in the Cloud? Well that is where XenDesktop comes in. Citrix XenDesktop allows you to take that PVS image and supply it to your end users virtually. Citrix XenDesktop moves beyond just the conventional desktop and into secure, on-demand, desktops as a service. Right now you’re thinking “That sounds awesome! But I don’t have either of those and they must be difficult to setup and install right?” Well they are easier to setup and install than you might think. Let’s look at the basic steps.

Step 1 – Gather the Components

This is probably one of the most difficult tasks. The system requirements for XenDesktop and Provisioning Services can be found here: Since you already have a hypervisor installed in your environment, you mainly need to decide how many CPUs and how much memory you want to be assigned to the VMs you create.

A couple quick notes for best practices: It is highly recommended to separate your Provisioning Server traffic from your production traffic by utilizing a separate NIC with a separate isolated VLAN and Subnet on the PVS server and VMs. By separating out the traffic, you will help ensure the quickest response time for your environment. In order to keep multiple images and revisions you will want to make sure you have plenty of space. A SAN environment is highly recommended however fast SAS drives on the provisioning server can also be substituted if SAN space is not available. Make sure that the space you select can handle at least 3 revisions of your desktop image for backup and restoration purposes (Don’t want to end up like Joe in IT do you?)

Step 2 Install the Software

Installation of the software components is relatively easy, with just a couple of clicks to run through. However if you are not feeling tech savvy, the great engineers at Accelera are always willing to help you out. Check out the Citrix EDocs site (Posted above) for step by step instructions on installing each product.

Step 3 Create your Image

Now that the software is installed, you are ready to create your base image. This can be Windows XP, Windows Vista, or Windows 7, pick your flavor and go through the basic installation procedures. Make sure that the VM has a NIC on both the production and PVS network. After you have completed the base installation procedures and/or updates, install the Provisioning Server Target Device Software and XenDesktop Agent and run the XenConvert wizard to place the image on the provisioning server. This part can be a little tricky as it requires that you have your vDisks on the provisioning server properly created and presented to your VM, so if you are looking for more in depth information than this blog or Citrix EDocs can provided, give the engineers at Accelera a quick call, and we can walk you through it in no time.

So now that you have the image you can take it and make simple VHD disk copies to have additional images you can manipulate without affecting this new “Gold” image. This is great for failback purposes.

Step 4 – Publish the Image with XenDesktop

With your image in hand (well stored on the Provisioning Server) it is time to publish it within XenDesktop. Running through and publishing the image to 50 VMs would be troublesome and take time. Citrix has been nice enough to provide us with the XenDesktop Setup Wizard. This Wizard (run from the provisioning server) allows you to take the one desktop image and make 50 desktops available through XenDesktop in a matter of minutes. Step by step instructions for using the XenDesktop Setup Wizard can be found here:

So now that you have the environment up and running. Any new clients are easy to add in minutes using Provisioning Services and XenDesktop. You have taken a process that used to take days down to a couple of minutes for simple clients or hours for more complex clients. Since you already have a hypervisor you can add hardware on demand without worrying about managing each individual piece or if one server fails it won’t affect the entire environment (remember always plan for an N+1). What about those pesky applications though? Providing a desktop is one thing, but installing and trying to manage all the applications is another. Well that is exactly what we will address in our next post.

"Tiered Virtualization" for "Value Engineering" virtual desktop solutions

Everyone who has looked at desktop virtualization or is currently looking at desktop virtualization is immediately drawn to its high cost. However, there are ways to "value engineer" a virtual desktop solution and make it cost effective for everyone. A virtual desktop solution is made up of many layers and each of the layers adds cost - ultimately driving the overall solution cost out of range for most organizations. One of the ways to reduce the cost of the solution is to leverage "tiered virtualization" which minimizes the cost of the hypervisor layer.

The concept of "tiered virtualization" is something that I defined based on Accelera’s motivation to make virtual desktop solutions more cost effective. The theory behind it: virtual desktop workloads are short term workloads by nature and therefore do not require the enterprise class features of a high-end hypervisor.

For example, you don't need VMWare vSphere Enterprise Plus to run a Microsoft Windows 7 virtual desktop. It doesn’t need DRS or HA (or for that matter any of the other features of the Enterprise Plus version) because the workload lifespan is typically no more than an 8 hour work day and then it's recycled.

Why spend the money on an expensive piece of software like vSphere Enterprise Plus to support this workload?

You can get away with free hypervisors like Hyper-V or if you're using Citrix XenDesktop you can use XenServer at no cost. This will reduce the overall cost of supporting a large number of virtual desktops. It's important to note that I'm not suggesting you stop using VMWare for all of your workloads, by all means you should continue using it for the mission critical workloads like Microsoft Exchange, Active Directory and application servers.

Virtual desktop solutions require a significant amount of virtual infrastructure to support a large user base. By reducing the cost within the layers it does become cost effective and the solution will demonstrate ROI. Continue following this topic, I will be adding other tips for “Value Engineering” your virtual desktop solution.

Virtualization How-To Part 1

So your company has gone through some growth. When you first started you had that one server with every single component installed on it. As the years have been kind to you, you’re now managing 80+ servers with separate functionality and role requirements. Failover and recovery is highly desired but your business is moving fast and you need something in place to accomplish this.

Step 1 is a virtualization assessment.

Those can get complex but in a nutshell they take a look at your existing environment and tell you which servers you could possibly utilize as virtualized servers. No one likes to re-buy all their hardware when there’s plenty available to use right? There are plenty of tools to do this and plenty of companies that will assist (including our awesome engineering team at Accelera Solutions) but if you’re looking for the quick answer, check out the FREE Microsoft MAP tool. You can run this tool inside your environment and it will give you the Cliff’s notes about which servers are candidates for virtualization.

Step 2 is choosing the right product.

Choosing a product really depends on many factors. What is your budget like? Do you have the expertise to configure something a little more complex than the others? Either way, when you start looking you’re likely to come across some of the key players:

1. VMWare VSphere

2. Citrix XenServer

3. Microsoft Hyper-V

Each product has key benefits and advantages which you can quickly find on the vendors’ websites. Here’s the quick and dirty on each…

VMWare VSphere – This one has been the giant in the industry for a while. It’s well established and contains a host of features. It does require a Virtual Center server AND license to do many of the advanced features (live migration, management of multiple servers, etc). The price can be a little steep for users just getting into virtualization and management can tend to be strenuous if you don’t know what you are doing.

Citrix XenServer – This one has joined the ranks of virtualization over the past couple of years and has quickly risen as a player. Key features are included in the price of FREE like live migration and iSCSI backend storage. If you're looking for memory sharing, performance metric monitoring or high availability, there are pricing packages for you. This product will allow you to get the environment up and running with the key virtualization features without the need to pony up the cash.

Microsoft Hyper V- It’s now included in the Windows 2008 operating system and even comes with 5 server licenses if you buy the Data Center edition of Windows. If you already have the Data Center edition of windows this one seems like a no-brainer. You can enable Microsoft clustering for reliability at no extra cost but some of the other features require the use of Microsoft SCVVM so read the fine print carefully.

Step 3 – Choose your Storage

Your choice of storage (where you store the actual VM file) is important believe it or not. If you choose slow storage, no matter how much RAM and CPU you throw at the VM it's going to run slow. When choosing your storage options, keep an open mind to various vendors and make sure to do your research. Of course, if you would like help with that research, Accelera has many vendors we can recommend for your specific environment. If you are looking for a quick fix for the test environment, consider using local storage on solid state drives or SAS drives. Keep in mind though that the products mentioned above require shared storage in order for the more advanced features to work properly (Failover, Live Migration, etc).

Step 4 – Begin Virtualization

It’s time to install it, configure it and of course start up some of your VMs. It sounds complicated, but depending on the product choice you made in step 1, it can be done in as little as 20 minutes. Most of the products allow for a step-by-step wizard and quick help options that will answer the majority of your questions up front. So now that the hypervisor is installed, let’s get some servers on it. But who wants to rebuild all of their servers to make them virtualized right? This is where the conversion tools come in.

Each product has their own version of a conversion tool to get VM workloads working properly. If you're looking for a quick tip, make sure the physical server you’re trying to virtualize is shut down when possible. By shutting down the physical server, you ensure that any services or files that are locked can be accessed. Boot the physical machine using the conversion disk and start the conversion process. Of course if your environment needs to remain “live” at all times, you can give the live conversion tools a try, but sometimes they don’t get those files that are locked. As always, make sure to test after the conversion.

Of course you are never limited to just the products offered by the vendor you selected. A quick Google search on “Convert Physical to Virtual” will turn up many third party products that can do the same thing as the vendor’s tools but “better”… at least according to their websites.

There you have it, now you have some of your servers virtualized. Next week we will look at solving those pesky desktop imaging problems.