There was a day when information technology personnel toiled behind the scenes to make their corporate computing infrastructure work.
But in the Internet era, those experts increasingly are getting starring roles in corporate computing leadership rather than being supporting cast members. Such is the case for Shelton Shugar, Yahoo's senior vice president of cloud computing.
"It becomes more a topic at cocktail parties," he said of his present job, which he took shortly after Yahoo formed the group in June 2008. "I was at a wine tasting, and an acquaintance said, 'I did a search on your name and found cloud computing. What's that all about?'"
Shugar isn't running any publicly available cloud computing services, be they nuts and bolts like Amazon Web Services or full-on applications such as Google Docs. Instead, he's in charge of building a computing infrastructure crucial to Yahoo's ability to operate at large scale and improve its services rapidly. Those are essential for the company's attempt to fend off Google, which arguably is nimble for its size, and start-ups such as Twitter or Facebook that can change course a bit more easily.
Shelton Shugar, Yahoo's SVP of cloud computing
(Credit: Screenshot by Stephen Shankland/CNET)"Most Yahoo properties you interact with use the cloud to some extent," said Shugar, who came to Yahoo from eBay and who's a headliner at the Cloud Computing Expo in November. "Over time, that percentage will continue increasing. Almost anything you touch uses some of it."
Most telling about his role: although rebuilding Yahoo on its own cloud-computing foundation is expected to save some money, the primary motivation is to liberate the company's programmers from the difficulties and drudgery of coding for gargantuan audience on the Internet.
"If we have a thousand developers who no longer have to build a lot of infrastructure, and who (instead) work on products and features, that puts us way farther ahead than squeezing a few nickels out of the infrastructure," Shugar said.
It's a mammoth chore. For example, when it comes to background data processing that underlies search results, behavioral ad targeting, site trend spotting, spam filtering, and Yahoo.com content selection, Yahoo uses open-source software called Hadoop.
"I've got 25,000 machines running Hadoop," Shugar said. They're divided into several "grids," the largest with about 4,000 servers. "It's a fascinating activity...watching the different dynamics of usage push things in different ways. Some tasks are very heavy on computation, some are heavy disk input-output. It's pretty complex."
Yahoo's 'private cloud'
Cloud computing is a popular buzzword these days, and as a result it means many things to many people. It generally refers to moving services to the Internet, which in innumerable technical diagrams over the years has been represented by, in fact, a cloud.
Cloud computing has grown less ephemeral in recent years, though. The Amazon Web Services suite offers a highly specific set of interfaces that Internet operations can use for everything from data storage to computing capacity. At a higher level, Google Docs lets people perform word processing and spreadsheet calculations through a Web browser. Microsoft is spanning that spectrum, working on its Azure foundation for generic Windows Server chores and on a Web-based version of Office.
One somewhat controversial concept is that of a "private cloud"--computing services that embrace some of the principles of publicly available clouds but that are used just by one company. If it's in-house only, what makes it any different from just the IT department's computers?
Yahoo makes a reasonable case that it's got a cloud of its own, though. It operates on a scale larger than many public cloud companies, and it embraces some of the principles cloud computing in that infrastructure.
For example, it's got a variety of interfaces that many Yahoo services can use--a concept often called multitenancy--so they don't have to build them on their own. For another, it's global, handling thorny issues such as operating at large scale and replicating data for reliability and responsiveness. And it's got a degree of elasticity built in, so the infrastructure can expand, contract, or otherwise adjust to changing work load demands.
This computing foundation is designed to ease the pain of developing Yahoo services. Some features and projects are easy to build at a small scale but hard to expand.
"It's like the cat going up the tree. It looks good at the beginning," Shugar said.
Yahoo's cloud services
Yahoo has four cloud services in varying degrees of availability:
• Operational storage, for housing data such as e-mail attachments or a user's social connections.
• Batch processing, for crunching oceans of data to sort Web search data, tailoring content and ads for individual users, and figuring out who's spamming Yahoo Mail.
• Edge content, for presenting Web pages, balancing the load from many users, caching data for fast use in many areas. This service is already in widespread use.
• Online serving, a flexible foundation for designing and housing complicated applications.
This last service is under development, due to arrive in 2010. "We're working with a few Yahoo properties as anchor tenants," Shugar said, declining to say which exactly.
The online serving interface will be based on Red Hat Enterprise Linux running atop the open-source Xen virtualization software offered by Citrix, Shugar said. "Virtual machines are going to get more and more and more important."
Though open-source software is freely available for the do-it-yourself crowd, Yahoo is in negotiations with some outside parties that will involve commercial relationships, he added.
Linux and virtualization
With virtualization, one server can house multiple operating systems at the same time, and operating system instances can be shuffled from one physical machine to another to adjust to changing demands. Yahoo has worked with virtualization leader VMware, but the company wants the nitty-gritty control enabled by open-source software.
"We need to be able to tweak it quite a bit for performance, to match it with our hardware," Shugar said.
Open-source software helps with Hadoop, too. Yahoo is the primary contributor to the project at the Apache Software Foundation, but others' participation helps ensure Hadoop stays generally useful.
Most people aren't going to wire up their own Hadoop computing cluster, of course. But "data center" no longer is a term understood just by server administrators and CIOs.
"There are these big data centers behind the scenes supporting all these searching, social networking, information-gathering activities," Shugar said. "Before, it was a business function inside a company. Now the awareness has increased as result of people using the Web. It becomes a topic of general interest."
The Xen.org community has announced plans to build a new cloud platform for service providers, as the basis of an initiative designed to help private and public cloud services cooperate using open standards.
The planned Xen Cloud Platform (XCP), announced on Monday, will combine enhanced security, storage, and network virtualization capabilities with the Xen hypervisor--a piece of open-source software used for running virtualized operating systems on server hardware.
However, a key goal of the wider XCP initiative is to use open standards from the Distributed Management Task Force (DMTF) to package virtual appliances in a hypervisor-independent format that can be transported between private and public clouds without vendor lock-in.
"Today Xen is already the most widely used hypervisor in the service provider market and the community will be able to build on this momentum to develop a complete, open source, cloud-optimized Xen virtual infrastructure platform," Xen creator Ian Pratt said in a statement. "Our goal is to (let providers) offer a rich set of services that will catalyze cloud adoption by the enterprise in a way that's open, accessible, and non-proprietary."
According to Xen.org, the XCP initiative will not try to develop new virtualization management tools for the bridging of public and private clouds, as this area is already well-served by commercial products and open-source initiatives such as the Eucalyptus project and OpenNebula.org.
Instead, the new initiative will build on storage, security, and network virtualization technologies that are "already under development as part of Xen.org," the community said. It added: "As a result, the new platform will not only address cloud provider requirements around security and isolation, but will also meet next-generation user requirements for security, availability, performance, isolation, and manage between on-premise and off-premise infrastructures."
Xen.org advisory board members including Citrix, HP, Intel, Novell, and Oracle are backing the XCP initiative, as are a host of other companies such as NetApp, AMD, Dell, Fujitsu, Juniper Networks, and GoGrid.
"Novell is committed to an open-source model that thrives on the support and contributions of a strong community," Carlos Montero-Luque, Novell's open platforms chief, said in the statement. "Creating a stable, well-defined public API for Xen will help drive its rapid adoption inside the enterprise and in clouds."
Oracle's head of Linux engineering, Win Coekaerts, added that "aligning the community around a single compatible code base will maximize the benefits of open-source virtual infrastructure for customers, and simplify the federation of private and public clouds."
The Xen.org statement said it wanted to bridge internal enterprise clouds with "external cloud platforms like Amazon EC2, Rackspace Cloud Server, and GoGrid." While Rackspace and GoGrid are both quoted as supporters of the XCP initiative, Amazon is not involved in the project.
Last week, Amazon launched a separate service, Virtual Private Cloud (VPC), for bridging private and public clouds. VPC is designed to let companies extend their security services, firewalls, and intrusion-detection systems to the cloud, and Amazon has indicated it will roll out the service--currently in beta--to all of the Amazon Web Services.
David Meyer of ZDNet UK reported from London.
Correction, Sept. 2, 4:53 a.m. PDT: This story initially miscast some background information on the DMTF.
Citrix has introduced updates to XenServer, its free virtualization platform, and to Citrix Essentials for XenServer and Hyper-V, its virtualization management package.
The new 5.5 release of XenServer, which Citrix began offering as a free download in February, is designed to provide easier virtualization management and broader integration with enterprise systems, the company said in its announcement Wednesday. This includes hooks that allow third-party products to interact with XenServer to provide full or incremental in-guest, file backups of virtual machines. Image backups are supported too.
In addition, it lets admins carry out GUI-based snapshots from the XenCenter management console.
The update supplies new tools to convert virtual machines from VMware's VMDK format into the VHD format used by Citrix XenServer and Microsoft Hyper-V. It also lets them switch between common open virtualisation format packages.
In addition, new search facilities give admins a range of ways to locate virtual machines, while Active Directory integration brings XenServer hosts into the enterprise's information repository.
The list of supported guests has grown in the new version of XenServer to include Suse Linux Enterprise Server 11, Debian 5.0 and RedHat/CentOS/Oracle 5.3.
As for Citrix Essentials for XenServer and Hyper-V, the new 5.5 version adds the ability to clone and provision XenServer or Microsoft Hyper-V-based virtual machines across physical and virtual resources. It also allows third-parties to deliver unified backup and snapshot features for the VMs.
Citrix said the Essentials update also simplifies the process of building, testing, sharing and delivering applications throughout an application's life cycle, including the ability to develop and test environments across virtualization platforms. According to Citrix, it also extends XenServer's XenMotion features by enabling automated movement of live virtual machines across servers based on preset rules and thresholds, so reducing performance bottlenecks.
The beta version of the new Citrix XenServer 5.5 is available for download now, with the final version scheduled for release on June 19. Citrix Essentials 5.5 for XenServer and Hyper-V is available now for download in a beta version and a 30-day trial version. It will also be released on June 19, with prices starting at $2,500 per server, regardless of the number of processors.
On Wednesday, Citrix also unveiled NetScaler VPX, a virtual appliance version of its NetScaler MPX hardware appliance that is designed to accelerate and secure enterprise web applications. It can be installed on commodity hardware, the company said. It added that the move should allow smaller companies to access its technology because the software appliance can be downloaded from the net and run on a standard server, making it cheaper to buy.
The company is pitching NetScaler VPX for use by enterprises and cloud service providers as an on-demand service, as virtual machines can be deployed quickly deployed as demand increases. The company has not yet announced prices.
Manek Dubash of ZDNet UK reported from London.
LAS VEGAS--The consumerization of the Web will be as disruptive to distributed computing as distributed computing was to the mainframe. That was the central theme of Citrix Systems CEO Mark Templeton's keynote speech at this week's Synergy 2009 conference.
Mark Templeton, CEO, Citrix Systems
(Credit: Citrix)This is an oversimplification, of course. Over the years, companies have run their business software in many different ways--not all of which are easily categorized as either mainframe-like or PC-like. One whole era of computing architectures during roughly the 1980s commonly went by the term "client-server." However, if we think of how distributed computing in the enterprise has evolved, this broad-brush statement makes a lot of sense.
That's because the enterprise PC isn't really a personal computer any longer. The administrative and security requirements around desktop and notebook devices running an increasingly complex stew of locally installed software have seen to that. In many enterprises, they're stringently locked down as a way to protect their often fragile software payloads from corruption.
This is a drum that virtualization and cloud-computing specialist Citrix has been pounding for quite a while. Writing after Citrix iForum (Synergy's predecessor) in November 2007, I noted:
We've seen and heard a lot of praise for the democratic impulse associated with this particular phase of computing that often goes by the Web 2.0 moniker. Anyone can post. Anyone can publish. Anyone can photograph. Your vote matters in social media.
And alternative ways of accessing and running applications have indeed made it easier to do things outside of a strict IT framework. In his closing iForum keynote, Citrix CEO Mark Templeton used the phrase "making the personal computer personal again" for this idea.
It's perhaps not too surprising that the proffered solution to this problem is a variety of technologies that Citrix collectively describes as application delivery. The framework to think about it is something like a satellite TV system. A controller, a delivery network, and a receiver transmit and receive the bits; they do so independently of the actual end-point device (i.e. the TV) and the content, so long as those adhere to certain interface standards.
One could use such an architecture to deliver enterprise applications to a truly personal notebook, an employee's personal system rather than an IT asset. Although still relatively uncommon in an enterprise context when it comes to PCs, it's a fairly common model with smartphones, though we're starting to see the beginnings of such an approach in the PC space too.
What this means specifically in a Citrix environment is that Citrix Delivery Center "head-end controllers" such as XenApp and XenDesktop advertise services--that is, applications that are available for users to run. New services or service updates are then loaded or streamed to a client.
One of Tuesday's major announcements was Citrix Receiver, which the company describes as "the first universal client for IT service delivery":
Under the hood, Citrix Receiver is a lightweight universal software client with an extensible browser-like "plug-in" architecture. Receiver comes standard with a variety of optional plug-ins that communicate with head-end infrastructure in the Citrix Delivery Center product family such as XenApp, XenDesktop, Citrix Access Gateway, and Branch Repeater.
These plug-ins support functionality such as online and offline app usage, virtual-desktop delivery, secure access control, password management, app acceleration, multimedia acceleration, service-level monitoring, and voice communications. This model enables IT to effectively operate as a service provider to their own employees, proactively and transparently monitoring end-user experience from a central location.
Receiver is available for Windows, Macs, and iPhones. Citrix also plans to support Windows Mobile and Symbian operating systems. It's also working with Open Kernel Labs to support Android. In all cases, Receiver is free.
In general, as with XenServer, Citrix' strategy is to make its money from the management and delivery software infrastructure rather than all of the base-level components.
The final announcement of the day was Dazzle. It's built on top of Receiver and accesses the same head-end services. It is, in a sense, Citrix application delivery meets Web 2.0.
I mean that in a somewhat metaphorical sense. But Dazzle is a self-service application store for employees that very deliberately and consciously mimics the conventions and approach of something like the iTunes Store. Web 2.0 and cloud-computing attributes, like self-service, device independence, and remote access are what help so many consumer applications make traditional enterprise apps look a bit shopworn by comparison.
And that's what Mark Templeton was talking about when he said the enterprise application delivery model is being disrupted by the consumer Web.
Citrix on Monday upped competition in the virtualization market with the announcement that it will provide a version of its XenServer hypervisor for free.
The software will be available for download by the end of March from Citrix's Web site, the company said. Users can get a single server instance of XenServer, said Simon Crosby, chief technical officer at Citrix. The release will include multinode management, resource sharing between several servers and full live-motion features.
However, Crosby told ZDNet UK that the free edition "will not include some features that we will continue to monetize."
Not included will be Workflow Studio orchestration, which is a tool used for automating common tasks, and StorageLink, which allows managers to directly provision virtual machines. To get these, users will have to buy Citrix's Essentials for XenServer package, which is priced at $1,500 (1,000 British pounds) for the Enterprise Edition, and $5,000 for Platinum Edition.
Jason Greschler, director of systems center management at Citrix's longtime partner Microsoft, said: "We welcome this move, which is in line with our ethos that these tools should be fast, free, compatible and ubiquitous."
Microsoft already offers its own hypervisor, Hyper-V, for free, together with a cut-down Server Core installation of Microsoft's Windows Server 2008.
Also on Monday, Citrix announced a deepening of its collaboration with Microsoft on server virtualization, in an effort called "Project Encore." The first results of this project will be the release of Citrix Essentials for Microsoft Hyper-V on 7 April. The virtualization management package will include tools such as storage integration and hypervisor interoperability for virtual machines based on both Hyper-V and XenServer.
"We see Citrix Essentials as a powerful extension that enables customers to accelerate their Hyper-V adoption in the enterprise in much the same way Citrix XenApp has extended the Windows Server platform for nearly 20 years in the application delivery arena. Microsoft also will work to ensure that a future release of Microsoft System Center will support Citrix XenServer for customers with mixed Hyper-V and XenServer environments," Mike Neil, general manager of virtualization strategy at Microsoft, said in a statement.
The Citrix announcements came the day before the start of VMworld Europe, a conference sponsored by and closely associated with VMware, the market leader in virtualization software. VMware also offers a free hypervisor package, based on its ESXi product.
Virtualization is growing fast, according to analyst firm Gartner, which has predicted that global revenue from virtualization software will grow by 43 percent in 2009, hitting $2.7 billion, compared with $1.9 billion in 2008.
Colin Barker of ZDNet UK reported from London.
It's been a year since Citrix bought XenSource, the company created by the founders of the Xen open-source hypervisor, and integrated the business into its lineup of products delivering applications to desktops.
As part of the process, Citrix made the XenServer virtualization software central to its strategy, and appointed XenSource staff to senior executive positions.
ZDNet UK sat down with one of those executives, Ian Pratt, Citrix's vice president for special products, to find out how the integration is going and where Citrix is going with Xen-branded products.
Ian Pratt, vice president, Citrix
In the second half of our two-part interview, Pratt talks about the impact of the Citrix takeover, the competitiveness and future of Xen, and more generally about the prospects for virtualization in a recession. (For part one, see "Q&A: Citrix exec says cloud to carry Xen against VMware.")
Tell me what's been happening in the past year. You've gone from being an independent company to becoming part of Citrix. But from the outside, it sometimes looks more as if Xen has taken over Citrix. Half the company's products have been renamed--Metaframe became XenApp and Desktop Server became Xen Desktop--Simon Crosby is now chief technology officer, and you're vice president for advanced products.
Pratt: Well, we've benefited from a larger channel. There are 5,000 people selling Citrix. But we don't immediately get 20 times the volume--there's a lot of training to be done. XenSource has been doubling sales every quarter, quite happily. Now as a start-up, we thought we expected to multiply by 100 every quarter, but doubling our sales is just fine.
We are seeing real benefits from integrating with the Citrix technology. We can make sure that (Citrix's) Xen Desktop works well with XenServer, for example. XenSource is now a new division in Citrix, for virtualization management. The chief executive (Peter Levine) is now a senior vice president--and both Simon and I report to him.
In fact, we haven't changed that much. There is more process in a bigger company, but from an engineering point of view, we are the same set of folks who wake up every morning wanting to stick it to VMware. We still have a start-up feeling.
Have you been asked to become more commercial? Have you had to go over to "the dark side"?
Pratt: In Citrix, we have not been asked to do anything against our genes. The open-source community has no problem with what we are doing.
Xen.org is being run the same way as it was before--but one thing Citrix has done is to fund a full-time project manager for Xen.org. If Xen got a bad reputation it would not in any way help Citrix.
It's not the only open-source hypervisor, though. Red Hat has been talking of the advantages of KVM, having bought Qumranet, its creator. Among other things, they say it will have long-term benefits from being integrated upstream with the Linux kernel.
Pratt: KVM is an add-on to the Linux kernel. It's hosted, not a true Type 1 hypervisor. It can never be a true Type 1 hypervisor. (Editors note: A Type 1 hypervisor runs on the bare metal of the server, while a Type 2 hypervisor is hosted on an operating system. Both VMware ESX and Microsoft Hyper-V are Type 1 hypervisors.)
With KVM you have the whole of Linux in the trusted layer. That includes device drivers and so on. And that is bad.
We also have broader support. You don't have to have Linux to run Xen. It runs on Solaris or BSD. KVM requires Linux.
Does virtualization itself still have good prospects? Is it the recession-proof part of IT?
Pratt: Everyone is doing it, and they are still doing it. Virtualization is a mature technology and the benefits to the bottom line are clear. You do it to save money, and people will continue doing that. The savings are immediate.
Having said that, some use cases may get pushed further out. For instance, some green sales may get delayed, where the motivation is partly reducing carbon footprint.
That's just where the company's IT power budget isn't reported clearly, surely?
Pratt: Yes. If the chief information officer's budget includes energy usage, then the company is more likely to deploy virtualization. But there are still plenty of companies where energy is treated separately, as part of the facilities budget.
So virtualization isn't absolutely recession-proof. Nothing is. But it has very good prospects.
Now is a good time to have a product that is a better value of solution. It's not a good time to be buying Rolls Royces. It's time to be buying Priuses. (Editors note: Earlier, Chief Technology Officer Simon Crosby compared Xen to a Toyota Prius and VMware to a Rolls Royce.)
As vice president for advanced products, what are you looking at?
Pratt: Client virtualization is an area I'm spending time on. It's an area where Xen leads--despite some bluster from VMware. It's an area where we can make a difference, and it will be driven by application delivery.
There will be virtualized smartphones on the market in the not-too-distant future. ARM has built virtualization into its processors; they didn't put that in for fun.
Virtualization in the embedded market will follow a similar playbook to virtualization in the x86 market. Client virtualization is going to happen quite quickly. It won't go through the phase where users have to choose their virtualization solution, because virtualization won't exist as a category. It will be part of the device when you buy it.
My other main area of interest is cloud computing. Between client and cloud, I have quite enough to do. They are both areas where Xen is a leader, and historically any area that wins on the client, ends up winning on the server.
A Xen presence on clients will bolster what we are doing on the server. And the cloud will help Xen, because it makes it easier to move virtual machines into the cloud. It will be possible to bridge from the cloud to the enterprise, so resources can be added dynamically.
Why pay for machines in the server room, when you can push them out into the cloud? In particular, functions like test and development, and disaster recovery, can be in the cloud. And if that cloud and the server room are both Xen, then it is much easier to do.
Peter Judge of ZDNet UK reports from London.
Citrix aims to beat VMware at virtualization. A year ago it bought XenSource, the company created by the founders of the Xen open-source hypervisor, and switched the Citrix business focus to virtualization.
Ian Pratt, vice president, Citrix
Citrix made XenServer, the commercial system based on Xen, central to its strategy, and applied a Xen brand to other Citrix products involved in delivering applications to desktops. XenSource staff gained senior positions at Citrix and have been setting the company's future direction.
Ian Pratt, the original project leader of Xen and a founder of XenSource, remains a Fellow of King's College, Cambridge, but is now also vice president for special products at Citrix--and remains chairman of Xen.org.
ZDNet UK spent a day at Citrix's U.K. headquarters with Pratt and his colleague, Simon Crosby, who has moved from chief technology officer of XenSource to become chief technology officer of Citrix. After lengthy briefings on Citrix products and the future of virtualization, we sat down with Pratt to understand where Citrix is going and why.
In the first of what will be a two-part interview, Pratt discusses how Citrix hopes to make headway in the virtualization market.
At the moment there is a lot of publicity for VMware and Microsoft Hyper-V. Is there a danger XenWare will be overlooked--especially as it is difficult to measure market share in virtualization? Could XenWare become the Liberal Democrats of virtualization?
Pratt: In the market, there is obviously a big incumbent player, VMware, and Microsoft has a very basic product that covers the low end. And then there is XenServer, which is going head to head with VMware, with an enterprise feature set.
If you look toward the cloud, all the cloud vendors use Xen. It gets used in all the largest deployments, by folks like Amazon and other large providers, because of all the features it offers.
It is very hard to judge what the market share is. With VMware, you just look at VMware's bank account.
But if you are looking at market share for Xen in general, you've got XenServer, Virtual Iron, XenApps, and products from other companies. And then there are all the Linux distributions that include Xen, most of which are free, and no one really has any idea of how many copies are in use.
Even with something like XenServer, because there's a free version, we keep stumbling into customers--particularly people doing software as a service, where it all runs on XenServer Express Edition (the free unsupported version of XenServer).
They haven't paid us any money as yet and they have thousands of servers running it. But we'd much rather they were running our stuff than VMware, because it's an opportunity for us.
With the Cloud Edition we recently announced, there will be lots of people wanting to pay for support and get features added.
If cloud providers are mostly on the free XenServer, is this the whole reason for the Cloud Edition--to turn them into "real" customers and start getting some money in?
Pratt: Simon Crosby has this analogy, that Xen is an engine and needs a car built around it. (The point of the analogy is that the Xen hypervisor is open-source, with a GPL license, so users can make additional technology outside that hypervisor and keep it proprietary, building commercial products that work with Xen.)
If you are a cloud provider or a big software-as-a-service (SaaS) vendor, you can download the open-source engine and build your own car around it. That's fine if you have the engineering resource to do that, but a lot of this stuff is going to become more commoditized. SaaS vendors don't all have very particular needs. They don't have to do this for themselves--they have just had to do it that way until now.
Cloud Edition gives them a standard framework, so they can just concentrate on the value-added bits that they are interested in.
So it's just like many software developments in the past, where it's become obvious that everyone is doing the same thing, and a supported version of that is produced?
Pratt: Yes. And they just switch over to the supported version.
So VMware is the big competitor, then. What is the state of things between you and VMware at the moment?
Pratt: VMware has been really successful as a virtualization vendor. But virtualization as a category will disappear. The basic use of virtualization--server consolidation--is now a commodity.
Virtualization will be included in every operating system and on every server. XenSource Express is built into every HP and Dell server, on a USB stick soldered into the box. Users can run multiple virtual machines on those machines out of the box.
This is the only thing VMware does, and it has 100,000 customers. VMware is preparing for this to happen, by building management tools. But this puts them in direct competition with huge established players, like Tivoli and HP OpenView.
Citrix's approach is to concentrate on application delivery. The function of an IT department is to deliver applications, and we are doing it end to end, from the data center to the client device.
We don't need to do systems management, and we don't need to compete head on. It is all about application delivery. People won't buy virtualization--but they will buy high availability and fault tolerance.
Citrix has 200,000 customers. That's a pretty good beachhead to deliver more Citrix stuff to customers.
What is distinctively better about Xen's approach compared with VMware's?
Pratt: We don't want to create a class of people called virtualization administrators who you need to manage your virtual machines. That's how VMware works.
VMware is operating system virtualization--or hardware virtualization. That puts a lot of effort into a problem that is no longer there (since modern hardware from Intel and AMD has evolved to support virtualization).
What we did was to start out with the idea that hardware should support virtualization and the virtual machine should be aware. We call that para-virtualization, and Microsoft calls it enlightenment. That's marketing.
If you employ virtualization to get a separation not just in the hardware layer, then you can compose things dynamically. That's the way to bring down the real cost of IT.
We want to be as much of an appliance as possible. We've always seen Xen as an appliance that hosts virtual appliances. You want it to be an appliance and manage it like an appliance. It's like a Netgear router--you just plug it in and go. Adding a new machine to a XenServer pool should be as easy as that.
It is also quite hard to establish the relative performance of VMware's hypervisor and XenServer because of VMware's licensing terms. Are you working on a way round that problem?
Pratt: The VMware EULA (end-user licensing agreement) prohibits the publication of any benchmark results to a third party. We tried to publish results in 2002, and that clause has been in the VMware EULA ever since.
As XenSource, we might have had fun and games around the policy, but as Citrix, we have to be more circumspect. It's possible to publish comparisons against "Hypervisor A" and "Hypervisor B," though.
How about comparisons with Microsoft? Pretty soon, Microsoft will be able to claim that all the people who have Server 2008 have Hyper-V, won't it?
Pratt: Yes, but then there will be the question of how many people are using it, and how many people have the bits. If we wanted to measure Xen market share like that, we would be in great shape, because every Linux distro has Xen included in it.
Peter Judge of ZDNet UK reported from London.
Xen has yet to reach Zen.
Xen's open-source standard for virtualization is gaining traction as cloud computing takes off, but despite claims by some companies that their Xen hypervisors outperform others, Simon Crosby, chief technology officer of Citrix, which acquired XenSource, had this advice during his keynote speech at LinuxWorld on Thursday: don't believe it.
"To say my Xen is better than your Xen is utter nonsense," Crosby quipped.
But while Xen, like its other virtualization offerings from VMware and Microsoft, are designed to allow a computers to operate multiple operating systems simultaneously to shift work demands among servers in an adaptable data center, the technology, while important, remains in flux.
Crosby's Xen evangelism comes as the industry faces growing competition from the likes of Red Hat and others that have begun touting KVM over Xen as their virtualization software.
And even within Xen, some competition exists, given its base bits change, resulting in different features depending upon when a snapshot was taken and built into a product. And another differentiator comes from the management tools that take advantage of the virtualization, such as tools that create new virtual machines to ones that monitor the machines if they become overburdened.
Despite competition from other forms of virtualization software, Crosby finds the use of Xen is growing. The Yankee Group, for example, estimates that 17 percent of the enterprise server market uses Xen, but Crosby estimates it may be more.
Xen, for example, is finding its way into laptops, as it addresses legacy workload issues, Crosby noted.
"Xen is everywhere in the clouds that I visit," said Crosby.
Xen has a development community to rally behind the virtualization technology and drive improvements and its integration into a range of products, other than just servers.
Nonetheless, challenges remain for Xen, such as virtual machines still tend to be tied to a specific hypervisor vendor and version, in addition, the technology is not verifiably secure.
Noted Crosby: "hypervisors are free...the next challenge is getting them ubiquitous."
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