A First Look At XenClient

If you’ve following our blog for a while, you know that XenClient is the new client-side hypervisor from Citrix. It’s purpose is to allow you to take your virtual desktop with you and still have an elegant way to keep it up to date and to synch your important documents. We’ve been testing the “Release Candidate” that Citrix recently made available as a public beta.

Even though it is obviously not finished code, it’s pretty impressive!

Our Dell Latitude demo system is configured with two VMs – one Windows 7 and the other Windows XP. Further I have Access 2003 installed on the XP image and Access 2007 installed on the Win7 image and I’m “passing through” Access 2003 from the XP VM to the Win7 VM. In other words, I can “publish” an application from one desktop – in this case, I’m publishing Access 2003 from the XP desktop – and “subscribe” to it from the other desktop. In practice, this is similar in appearance to how a XenApp published application looks when it runs on the client device.

There are a couple of advantages to this. The obvious one is that an application that won’t run on Win7 can be installed on the XP desktop and made available to the Win7 desktop. A more subtle advantage is in the area of security. For example, let’s assume that the XP desktop is your “business desktop,” and is locked down such that the user has no administrative rights. Let’s further assume that the Win7 desktop is your “personal desktop,” and you have the rights to do whatever you want with it – which could include getting infected with malware. But the applications running on the business desktop cannot be affected by malware on the personal desktop – even if they’re being passed through.

In an earlier blog post, we linked to a Citrix TV video that demonstrated this “secure application sharing.” In that video, they’ve deliberately infected one desktop with a keylogger. You can see that any interaction with a browser running on that desktop is being logged by the keylogger. However, a browser session that is running on the other desktop, but being passed through to the infected desktop, is immune to the keylogger. Pretty cool.

With regards to functionality, I’m very hopeful that Citrix will fix some of the issues we’ve seen in the RC. Here are some of the things we’ve seen reported on the Citrix on-line forums, some of which we’ve seen ourselves:

• Many people are finding hardware problems with simple devices such as mice even for hardware on the Hardware Compatibility List. Smart cards are also an issue.
• XenClient requires that a few different Virtualization technologies be present in order to function correctly, so today the HCL is pretty limited. This should be improving each day but it is still something to watch out for so be sure to check the HCL carefully. There is an HCL included with the XenClient 1.0 RC User Guide.
• HDX (High Definition) video/audio:
  • If you run both a corporate Desktop and a Personal desktop at the same time, only one VM can have HDX running at a time – and to switch HDX functionality between VMs you have to shut them down…it cannot be done on the fly. This is unfortunate because without HDX, video is really choppy and difficult to watch. Citrix has already said this will not change before RTM (Release to Manufacturing).
  • If you are taking advantage of the feature we described earlier where you publish an application from one desktop and subscribe to it from the other, you can have HDX running in the subscribing desktop, but not in the publishing desktop.
• We’ve not yet been able to do a successful physical-to-virtual (“P2V”) migration of a desktop OS into the XenClient environment. Citrix has said it will release a version of XenConvert that will be able to do this, but they say it probably won’t be until after RTM.
• Integrated video cams do not work. This could be a significant issue, since the product is aimed at “road warriors” and many of them will want to use a cam for meeting. It supposedly supports USB video cams, but we have not yet tested this. However, I’m concerned that many users will push back on having to carry an extra peripheral with them. We’ve been told by Citrix that this should be working by RTM.
• OS Snapshots are not available yet but should be in a future release.
• No support for 64 bit guests yet.
• Graphic support for non-Intel graphic chip sets is limited.

Still, this is shaping up to be a great product that will make life easier for many a desktop administrator. If you’ve ever had to manage desktops, you’ve had to deal with this “Catch-22:”

1. My users are breaking their desktops…I need to lock them down.
2. When I lock them down, I end up with managers in my face because they can’t install their favorite (fill in the blank).
3. I back off and give them local admin rights so they can install (fill in the blank).
4. Return to Step 1, repeat ad nauseum.

XenClient gives us a glimmer of hope that we may be able, sometime soon, to break out of this cycle!