Citrix XenClient, first thoughts
Posted by Jim Moyle on May 18th, 2010So I’ve had a chance to play with the new Citrix XenClient Express RC for a couple of days now, I was lucky enough to have a laptop on the HCL (a Lenovo T400) with enough RAM to cope with multiple VM’s. When testing I’ve tried to keep in mind that this is a a 1.0 release candidate and not as yet ready for production. Ian Pratt has famously said that if he knew how hard this was going to be he wouldn’t have done it, so was all that effort worth it?
Installation
Installing the XenClient host software was very easy and went exactly as it was supposed to, although there is no option to slip the hypervisor under the OS, or backup and retrieve the OS, so as yet, no in place upgrades are possible. Whether it is possible to use XenConvert or Sysinternals disk2vhd to create a VHD, load it into the Synchonizer server and redeploy I don’t know, it’s certainly not a documented feature (edit: See comments).
There is two parts to the host installation software, though both install as one, the Xen hypervisor itself and what Citrix call the Citrix Receiver, now this is what they usually call their client software, so presumably it will act much more like it’s namesake later.
Installing the Synchonizer server was equally as simple, just import the xva into a XenServer and spend a couple of minutes configuring it as per the documentation. I’m not surprised that there isn’t an option to use Hyper-V or ESX at the moment, although Citrix have shown that they are willing to port their virtual appliances to other hypervisors, so I wouldn’t be surprised to see the virtual appliances arrive on competing hypervisor products at some point. At this point I would recommend a little bit of further configuration, which I will cover below in the XenClient with Synchronizer section.
Guest Installation
Creating the VM’s is again very simple, pick your OS, RAM and vCPU’s and that’s about it. One issue with creating the VM is that the wireless card can only be used in shared mode, while the wired card can be used in the more traditional shared, bridged or host configuration. This means that you can only use NAT with the wireless card, this could of course cause issues. For instance you can’t configure an extra IP address on the card. I get the feeling that getting the wireless networking to work was one of the harder things that Citrix had to do.
So far, supported Guests are limited to Windows 32 bit client operating systems, Windows XP, Vista, and Win 7 32-bit. I decided to install Windows 7. There is no option to mount an iso file and I had to search around to find a burner to produce the installation disc. Windows 7 installed without a problem, though I felt perhaps a little slowly. This may just have been a case of a watched pot, but I think without the guest tools installed, this would make sense.
The XenClient iso is automatically mounted into the operating system on boot, although this is the only iso file you can mount using the hypervisor. The installation of the XenClient tools was very temperamental, either giving errors or missing installing the audio device. The installation takes a while longer than I’m used to, but I suppose it’s doing a lot more, after it’s finished two reboots are required.
Experimental Features
The two experimental features available are 3D support and application publishing. I hope that both features make it off the experimental list and onto the supported list by release.
3D support is configured by enabling it within the Citrix receiver console and installing software in the guest VM. This went pretty smoothly, I took a couple of screenshots of the windows experience index before and after the 3D was enabled, unfortunately I didn’t take a screenshot before I wiped my laptop to give the best comparison, but here are the two shots:
Before 3D
After 3D
As you can see the 3D performance is dramatically better. How close it is to native performance I’m not sure. 3D can only be enabled on one running VM at a time. Also you can’t publish applications from a 3D enabled VM, presumably as the publishing protocol (modified ICA?) can’t handle the difference in screen output.
Application publishing seemed to go well and worked as documented. You need to install software on both the publishing VM and the receiver. I wonder if the traffic goes over IP or through the hypervisor, through the hypervisor would be more secure.
Peripheral Support
What is and isn’t supported seems to be a bit of a mystery at the moment, I can’t find any documentation on which classes of device are supported.
The extra buttons on my mouse don’t work, this is apparently because all mouse and keyboard input goes through the hypervisor and the more advanced features are not supported, I would guess that this means any proprietary buttons on a keyboard would be non functional too. This is actually a much bigger problem than it might appear, with any new tech user acceptance is key and taking away functionality from such basic things as mouse and keyboard would affect almost all users and cause numerous complaints.
USB hard drives worked fine, except they were not recognised on boot, they had to be unplugged and re-plugged to be picked up, presumably the tools need to be running before the device is plugged in.
My USB headset was not recognised at all, despite the drivers being native to Win7.
The fingerprint reader on the laptop also wasn’t recognised.
Although I didn’t have a webcam to test, there are a few forum posts complaining about lack of functionality. Citrix say they are hoping to have these in by release.
I said before that Wireless support was one of the harder things to do, I think that USB support may well be the other thing they had trouble with. In device manager I always got a non functional USB hub, whether this is just me or an issue with the tools I don’t know.
XenClient with Synchronizer
Creating the template VM was simple, though remarkably slow, my transfer rate was between 500 and 2,500 kbps, this really needs to improve if you are transferring Gigs of data. I then created a new VM and used the template for install, again worked fine, if painfully slow.
I then installed a few apps and took a backup of the OS, after which I destroyed my local VM. Restoring it worked, but first the client downloaded the six Gig template image, then the 10Gig of backup, why not just restore from backup? This also happened at a snails pace, I had to leave it over night 
.
Additional users can be created in the synchronizer or imported from AD, once there though they can’t be deleted. This is due to issues with checked out VM’s.
One thing with the Synchronizer appliance, it starts with a default of 20Gig disk space, this will obviously get used up very fast. Either you can connect it to an NFS share or expand the disk, I’d advise you do one of these at the very start to avoid space issues.
The Synchronizer seems to be very basic at the moment, I’d expect the feature set of this to be expanded before release.
Other stuff I tried
Windows 2008 server (32 bit of course) installed OK, and seemed to work fine, but installing the tools broke the wireless networking. If you don’t need wireless I don’t see why this shouldn’t be absolutely fine.
Ubuntu wouldn’t install, it hung very soon into the process, though it would run live from the CD.
Is it any good?
I have to say I’m impressed, the consoles were snappy and easy to use, apart from some issues with installing the tools everything worked as documented. I expected the USB support to be iffy and the HCL to be small. both of these will improve over time. The HCL especially will get better quickly as Dell and HP OEM XenClient and add their own drivers.
Peripheral support is a big deal, they really need to get USB support as close to native as possible, or acceptance is going to be hard.
Guest support is OK, though Linux guest support needs to arrive quickly, one of the major benefits of having a client hypervisor will be having 3rd party virtual appliances sitting in the background. I’m sure this is where major innovation and value add from third parties is going to come. Without Linux support, that’s not going to happen.
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