It’s that time in the XenApp world again… Migration.  With the release of XenApp 5, many of you are contemplating a migration.  Why is migration such a big deal? I’ve heard numerous reasons like “It takes a long time to test my applications with the new XenApp (especially true if there is a new operating system involved)”, “It takes a long time to rebuild my servers as I have to update my server build scripts” or “My current XenApp environment works fine, so why change it”.

Those were all good points a few years ago.  But with the enhancements and optimizations made on XenServer for XenApp virtual machines, it is a great time to test server virtualization for XenApp to simplify migration.  And if we virtualize the XenApp servers, migration to XenApp 5, 6, 9, 11 or even XenApp 243 will be even easier (of course we will have changed the product name a few times. Let me hear a Hallelujah for HomerFrame or XenHomer).

But if we are going to migrate to XenApp 5, why not make the migration easier. Just how will XenServer make migration easier?  That is a great question, and I’m glad I asked it

Hardware
First, part of a new XenApp version means organizations will have to update their server builds.  Many of the server builds I’ve seen are complex scripts or require many manual changes once the build is complete.  Many times, there are multiple builds because of differences in the underlying hardware.  With XenServer , the links between the OS and the hardware are cut resulting in the ability to create a single build that can span multiple hardware variations.  How many fewer images will you now have to maintain?  Simplified

Optimization
With XenApp, you want to get the most users out of  your hardware.  This has been true with previous versions, is true with XenApp 5 and will be true in the future versions.  With a new OS and a new XenApp, do you have any idea how much hardware you need to support your users for the different application sets?  This is a challenge, especially when trying to design the new environment.  When you designate a server for a certain function, it is awfully hard to change the server’s function, unless you virtualize.  With XenServer, you can make a virtual machine into anything you want.  You can move the running virtual machine to another physical server without the users ever knowing.  With XenServer and XenApp, you are no longer stuck in your static environment; instead, you are dynamically changing the environment based on the needs of the business. Simplified

Maintenance
How many of you like spending your days patching servers?  Not many.  Unfortunately, with each piece of software, there will undoubtedly be patches. With physical servers, you have to patch each server. With server virtualization, you still have to patch each virtual server.  But with XenServer Platinum, you only have to patch your base image, which is delivered to the virtual server via Provisioning Server.  If I have one XenApp image for SAP and another XenApp image for all of my other applications, I only have to patch both of those images.  Those images are then streamed to hundreds of physical or virtual servers.  Simplified

Evaluate
How could we do a migration without evaluating the apps and OS and XenApp configuration? This is critically important, especially if you are upgrading to a new OS like Windows Server 2008. With XenServer Platinum, the evaluation and testing phase is simplified.  How do you typically do this?  Well, you build the environment in a test lab.  You run test, modify, re-test. The cycle continues until a golden image is created.  That image must be used as a guide for rolling into production.  If you use scripts, you have to figure out how to script the build process to mimic your image.  If you use cloning solutions, you have to modify based on hardware.  If you use Provisioning Server, which is part of XenServer, you take your server, create a Provisioning Server image, and copy the image to production for delivery.  Simplified.   

Rollback
Let’s say you upgraded without doing a proper test (shame on you).  As it turns out, one of the applications, which unlucky for you, is mission critical and is not working correctly.  What do you do?  Well, you have a few options:

  • Try to troubleshoot and fix. You will be under the gun to get it fixed quickly as the business needs the application.
  • Rebuild the physical server with the old setup. This will take a few hours for the build to complete and configure the applications.

Neither of those options sounds good to me.  Instead, if the environment was virtualized with XenServer Platinum, you would easily be able to change the version of XenApp delivered based on the Provisioning Server image you associated with each target device.  Simplified

XenServer for XenApp can simplify migrations by focusing on the areas of Hardware, Optimization, Maintenance, Evaluation and Rollback (This is what I like to call the HOMER Criteria).   It’s a great way to get more done without working harder.  You get the migration done faster while providing a more dynamic environment for the business. 

Daniel