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Citrix and Xen - the Fruity Flavored Path to Nirvana

XenSource is now going to be a part of Citrix, an interesting move that answers a question that a lot of Citrix aficionados, myself included, were wondering – “What is Citrix doing to remain relevant in the face of Virtual Desktops?”. Virtual Desktops are what this is really all about. Citrix is not a server company, it’s a delivery company. In terms of quality and speed, you can make the comparison that Citrix is the FedEx of bits and bytes, if you will, to Micrsoft’s US Post Office. Citrix, with its ICA protocol, is like FedEx in that it is faster, more full-featured, and more expensive than the trustworthy old Post Office of RDP. Citrix may make a line of server products, but their business is in getting applications into the hands of end-users regardless of distance, client operating system, link speed, and other factors that typically inhibit deployment. Whether this is done by granting remote access to applications over the web, over a proprietary protocol, or any other method has been irrelevant to Citrix for some time – they adapted quickly to the web, enabling ICA-delivered application delivery as early as MetaFrame 1.8 in the late 90’s. What was always a problem in the Citrix world was the full desktop – Citrix’s own CCA (Citrix Certified Administrator, a cert I hold near and dear) training pushes for application delivery over desktop delivery, and for good reason. Presentation Server, the successor to MetaFrame (which was the successor to WinFrame) runs on a Windows server, and there are as many inherent risks of letting people have remote desktops on a server as one can imagine, not the least of which is registry corruption and accidentally deleted files that can hose the entire server, as well as disk space issues. Imagine 50 users saving the same 200MB PDF or PPT of the company’s end-of-fiscal-year financial report on their desktop instead of a network file directory, and you can see how the problem would start. Couple in the complexities of antivirus / antimalware and you can picture the resource spikes every morning at 9am when 20 users log on and the AV program starts running it’s at-logon full computer scan 20 times. While some AV products are Citrix / Terminal Services aware and can be configured not to do this, that’s the exception, not the rule – most often the schedules need to be changed from the default of daily scanning on logon that many companies use and adjusted to only a once-daily at a fixed (off-hours) time. Then of course there’s the resource issue – one errant application that cpu-locks the box takes it away from everyone, because it’s all really just one computer. While Citrix has made many inroads to mitigating these problems, they still exist, and make full-featured Citrix desktops hard to manage and hard to justify on a large scale.

What XenSource adds to the Citrix portfolio is a virtual desktop platform without the caveats of the delivered desktop being part of the same server OS as the application – each desktop can be shunted off onto shared storage, is it’s own contained OS, and can be delivered seamlessly without other users vying for resources. There are still resource issues to contend with such as CPU locking, but because virtualization allows for greater restrictions on access to the physical hardware, these can mitigated faster and without large-scale interruption. The same applies to memory locking, but to an even greater extent – since a VM has X-amount of memory, you can lock it all up and not affect the other virtual machines much at all. No doubt Citrix is working on perfecting desktop delivery of Xen-based desktops over ICA. Likewise Citrix is no doubt working on integrating their already-impressive management tools (MetaFrame XPe even had a configurable chargeback function built in from it’s initial release!) to make managing Xen desktops easier. What’s further is that this gives Citrix a hedge against the possibility of Linux desktops making significant inroads into the enterprise market in the next few years. Instead of depending on Windows, Citrix has just become open to delivering multiple flavors of Linux, BSD, and many other operating systems to users who need them.

What about running Citrix on Windows on Xen host servers? I don’t think Citrix cares one way or the other if you do – it’s still a license for the software regardless of whether the host is virtual or physical, so other than a marketing play about getting scalability on virtual hardware, there’s not much advantage to be seen. Thin Clients? Citrix doesn’t sell them, but they have very cozy relations with all the TC vendors out there, especially Wyse. Wyse has already made great inroads with VMware virtual desktops, and it’s sure to follow that they’ll support Xen desktops as well.

What if I’m wrong? It’s a good possibility. And I’m sure that Citrix sees the other side of the coin – the death of the full-featured desktop as we know it, with a glorified web browser supplanting it. Indeed, this would be the ideal Semantic Web / Web 2.0 client operating system – all applications occurring in a browser, with nothing on the user’s side that can really break, or take a long time rebooting, or need a lot of skill to repair, or require complex driver slipstreaming into images, etc. etc. Just a browser and some horsepower to help the client-side of the web-applications get processed is all anyone would need for an all-web-application environment. This is basically just a distributed thin client, with a slimmed down OS and remote application delivery. This just happens to also be the business Citrix has been supporting for decades. Many of these applications, so thin to the end-user, are fairly large on the server side, and being able to provide virtualization of those apps will keep Citrix relevant when the user’s choice of client no longer matters because everything is designed for web delivery. Right now that’s a selling point for Citrix – they have an ICA client for almost every OS out there, giving people on Linux access to Windows apps without messing with WINE, giving remote users with limited bandwidth access to giant client-server applications. They have web-enabled gateways to allow this to happen over a browser (with a plugin). The trouble with ICA is that if the need for specialized software to connect to remote systems diminishes as more and more applications because browser-based, the need for such a system dependent on plugins and other protocols wanes, leaving Citrix’s ICA out in the lurch. So, either way the cookie crumbles, Citrix has a smart, effective strategy for maintaining relevence.

There are many questions unanswered, such as what will happen to future Xen development? Will Citrix close any new Xen code or keep it Open Source? What will happen to Virtual Iron? Will Xen fork? What will happen to the long-standing but sometimes strained relationship between Citrix and Microsoft? Stayed tuned… this is an interesting time for virtualization and Citrix followers, and I would expect a lot more blogging, reporting, and gossiping about what this means in the very near future. IT Managers should keep an eye on their Virtual Desktop initiatives, for sure. Overall, I would expect this to be a very positive thing for virtualization on the server, desktop, and application front. Disruptive, no doubt, but positive.