Interview with XenSource founder Simon Crosby

In early April, Moscow hosted another Citrix partnership conference, which was attended by Simon Crosby, Technical Director of Cloud Computing and Data Center. Simon is a very charismatic leader, humorously describing his position as the “main religious fanatic” on strategic development issues. He also stood at the origins of XenServer, was CTO at XenSource, which was acquired by Citrix Systems in 2007.

In a special interview for the Citrix blog on Habré, Simon spoke about the commitment to an open software development model and close cooperation with Microsoft, about the rivalry with VMware and the future of cloud systems. Simon is a consistent advocate of an “open” software development model, but at the same time largely disagrees with Richard Stallman's ideas. According to Crosby, open source is rather an effective tool for cooperation between companies and the community, equally interested in developing an effective product. The XenServer hypervisor, and after moving under the wing of Citrix, is open source and, in itself, is free. Community participation in the development allows the release of new versions of Xen twice a year, and free, according to Simon, is a good way to “annoy” Citrix’s main competitor in server virtualization.


About XenSource

Xen was originally a project of the University of Cambridge, work on it began in the late 90s. Like many other academic projects, its source code was originally open. Over time, the project became popular, it began to be used by commercial companies that needed support. This was the reason for the formation of XenSource in 2005, and then Xen had two major advantages. Firstly, we had open sources, which the main competitor, VMware, did not have. Secondly, Xen was then the only alternative to the products of this company. And since competition in any market is a blessing, we have received serious support from companies such as IBM. They, for example, provided a secure hypervisor architecture, and the US National Security Agency participated in the development of encryption modules. Over 200 programmers actively worked on the project, and it developed at a very fast pace. We started with a serious lag behind VMware, but literally caught up with them in a year and a half.

When Citrix acquired XenSource in 2007, our server virtualization market share was around 3-4 percent. Now we have grown to 15-16 percent. Microsoft's Hyper-V hypervisor is also gaining market share fairly quickly, so VMware now has very serious competition in the market. Although they are still leading, and this is with them, admittedly, it turns out pretty well.



About competitors and desktop virtualization

You need to understand that Citrix does not make money selling server virtualization technologies. According to Gartner, only two products on the market are ready for use in large companies, on the most “heavy” projects. These are VMware vSphere and Citrix XenServer. However, we do not monetize this market segment at all. Why? We believe that virtualized infrastructure is an essential, but not the main part of our core business, desktop virtualization. For the work of many virtual desktops, a hypervisor is naturally needed, but this is not the main function, just one of many.

At the same time, we have technologies that allow you to deploy private and public cloud systems based on XenServer. But this is also not the main part of the business. In this segment, we earn more on network solutions such as Citrix NetScaler. Networking brings a significant portion of revenue — for Citrix, this is about $ 300 million a year. If we go back to desktop virtualization, I’m sure that by the end of next year we will be serving a million servers with XenServer that provide exclusively desktop virtualization.

We decided not to make money on server virtualization for several reasons. First, historically, this is not the main activity of the company. We have great partners like Microsoft with its System Center and Hyper-V that provide infrastructure automation. Microsoft, like VMware, makes money on this, but we do things differently. Citrix solutions are sold to people in the company responsible for delivering custom applications and desktops. They have always been our main customers. We simply focus on the strengths of our business, and we are the undisputed leader in desktop virtualization. Over the past three quarters, we have virtualized over 10 million desktops.

About cloud computing

Any cloud system includes Software as a Service and InfraStructure as a Service components. As for SaaS solutions, we are now the fourth largest supplier in the world and plan to further develop this area. We are also developing IaaS cloud solutions. We are participating in the development of an open project, OpenStack, which is the only alternative to the VMware vCloud initiative. Our solutions run the most ambitious projects, such as RackSpace and Amazon EC2.



Thanks to this experience, we know how to build large-scale public cloud systems. However, we are not going to directly compete with VMware vCloud in the private cloud market. They sell an IT infrastructure automation system. We have never worked in this particular niche, although the cost of our cloud systems now is less than 1/20 of the cost of the same system on VMware solutions. We can develop enterprise cloud systems based on open technologies, fully automated and at a much lower price. Such systems can be used for desktop virtualization and in the development of next-generation web applications, and this is not about more and more advanced IT automation systems.We create corporate cloud systems that allow application developers to simply develop applications. No connection with IT, that’s the main difference. We are building clouds, which provide for the presence of one specialist for 10 thousand servers. And not one in a hundred or so, in the case of vCloud.

There are two directions for the development of cloud systems. In the first case, IT professionals are using vCloud for increasing automation. We build developer-oriented clouds. Everything is done just for developers who create applications and implement them in cloud systems; IT in this case is out of the question. Amazon EC2 is not served by people, there are none at all.

To summarize. Our model of the cloud system is fully automated, built on the basis of standard servers with local data storage, a large amount of RAM. The cost of ownership of such a system is 60% lower compared to VMware solutions, it is the cheapest infrastructure for next-generation web applications.



About Citrix Development

Citrix is ​​the fourth largest SaaS service provider, and this area is developing very rapidly, especially in European countries. The desktop virtualization business is developing at a slower pace, much faster than server virtualization. We can say that virtualized servers captured 30-40, maybe 50% of the market, but virtualization of the remaining 50% is a very difficult task. Desktop virtualization technology, when the virtual user OS is launched in the data center, is attractive to 15%, perhaps 30% of companies. This is not enough. What to do with the remaining 70% using "real" PCs?

We tried to answer this question by developing the XenClient Embedded Client Hypervisor. It allows you to work with virtual desktops both when connected to the network, and without it.
At the same time, it provides the same degree of reliability and security of corporate data as the classic virtual desktop. If a laptop with XenClient and a corporate OS is stolen, it will still fail to read encrypted data. If the laptop breaks down, I can continue working at any time with the same copy of the virtual OS and the same data on another device. Therefore, we see serious potential for growth in XenClient, the solutions embedded in it are attractive for a wide range of companies, especially for those who need maximum data protection.

Another actively developing area is new types of client devices, tablets, smartphones and so on. These devices are included in the corporate work environment, and there is a need to access Windows applications from iPhone, iPad or something similar. At the same time, a modern tablet is not a thin client, it has a fairly powerful processor, a productive video system. Tablets have seriously affected even the classic PC market, and our task is to provide access to data, user settings and applications on any device.

About open source

I am sure that Open Source is the most productive software development model. Take for example Xen. The number of developers needed to create a truly successful hypervisor is about the same for us, for Microsoft or VMware. Only they have to hire 300 people for this, provide working conditions for them until they, working “from call to call”, release the product. In the open source world, things are completely different. Xen is being developed 24 hours a day, all over the world, and I personally do not pay for it. Collective software development ensures the best quality of the code, by evaluating the contribution of each participant by the community. Thus, the quality of the code is higher, development is ongoing, the most modern hardware is supported. The finished product is used by many companies in a variety of tasks.



We release significant updates to XenServer twice a year. Compare with other software manufacturers. VMware took three years to develop vSphere, while Microsoft usually has a two-year development cycle. But we are not limited to XenServer. Our entire arsenal of cloud technology, part of the OpenStack project , is fully open and developed by the community. About 200 developers from 50 different companies work on this project daily.

Such a platform requires maximum openness, so it should support any hypervisor, be scalable and ready to manage the largest clouds. Therefore, we also added support for ESX, Hyper-V, KVM hypervisors to OpenStack, not counting XenServer. This project is developing much faster than vCloud. In fact, if you evaluate the pace of vSphere's transformation into vCloud, you can conclude that OpenStack will get better support for VMware solutions than vCloud itself .

About collaboration with Microsoft

We have a great relationship with Microsoft. Back in the days of XenSource, we had a separate team in Redmond that worked on Hyper-V, we were fully responsible for development on the Linux side. And there were no problems. We also added Hyper-V support to OpenStack, and you can use the Microsoft hypervisor to build a large cloud system. We work productively with Microsoft in the field of application delivery. But in the world of cloud technology, we are absolutely sure that the customer should be able to use any hypervisor. By the way, XenServer is 100 percent compatible with Hyper-V. You can take the virtual machine from XenServer and just run it on the Microsoft hypervisor.

We try to prevent competition. Microsoft has a System Center with an extensive set of solutions for automating data centers. We do not do this, but for them it is a profitable business, they can compete in this direction with VMware. We are actively working in the field of desktop virtualization and application delivery.