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These are my notes summarizing Brian Madden’s one hour long Terminal Services versus VDI presentation at VMWorld Europe 2009. I will highly recommend that you should watch Brian’s video, he is insightful, lively and articulate, you’ll enjoy him while learning from it as I did.

Background

Both Terminal Services (TS) and Virtual Desktop Infrastructure (VDI) employ server-based computing (SBC) and offer the benefits that are inherent to SBC, namely

• Central management
• Central access control
• High performance
• Security

Historically, several applications have been found not to work with SBC due to limitations of remote display protocols, although the end-user often views it as an application compatibility issue. Typically applications that are multimedia, graphic-intensive, or write their state to proprietary folders on a local disk drive, or require multiple monitors, or a hardware security dongle,  are known to break.

Should I use TS and VDI?

If you have to answer this question, you should first identify which applications are SBC compatible. Once you have identified them, then you should decide between TS and VDI.

TS advantages:

1. Very high user density (By contrast, VMWare VDI supports only 6 to 8 users per core today)
2. Proven solution/Mature technology (80 Million users/lot of user experiences on wiki’s  and training material on the Web. By contrast, VDI is cutting edge, there is a learning curve coupled with a dearth of usage-based content)
3. Automatic “thin” provisioning: All users share a common copy of OS/app code

VDI advantages:

1. Live migration for load balancing, supporting mobile users
2. VM’s can be rebooted without rebooting the host
3. Suspend/resume of VM’s possible (TS disconnect continues to consume resources)
4. Fault tolerance per user (since each user has their own VM)
5. Competition amongst vendors (Citrix was a monopoly for TS, now VMWare, Microsoft, Citrix and several other vendors are investing in the future of VDI)

   Brian showcased Atlantis Computing as an innovator that dynamically composes a bootable virtual disk (vhd or vmdk) for booting a VM.

VDI disadvantages:

1. Disk space: 10GB per user in the data center (cost per GB in data center is 5X to 10X its cost on the desktop)
2. Routine Op’s: How to run AV, backup, patch one master image

Brian’s predictions for 2010:

• Improving user density
• Remote Display Protocol improvements
• Thin provisioning/ Windows layering
• Offline VDI/Local hypervisors
• Local personality/Application management

Brian possesses journalistic flair; his posts are always insightful and thought-provoking. I have become a great fan of his blog.

Migration to Windows 7 is an impending event and it will happen, since Windows XP was released in 2001 and is already over 7 years old, while new generations of processors (multi-core, 64-bit, Intel VT), chip sets, graphics cards, audio cards, and disk interfaces (e.g., SATA), which were developed after XP gained mainstream adoption, are already shiiping in commodity computer hardware today.

63% of all desktops/laptops/workstations worldwide use XP, 23% use Vista; the remaining market share is fragmented across other Windows, Mac, Linux and OS’s mobile devices. [Net Applications Operating Systems Market Share report.]

XP has lost 10% market share between May 2008 and March 2009, while Vista gained just over 8% [Net Applications Top Operating Systems Share Trend report.] I am presuming that 8% of the XP users migrated to Vista and the remaining 2% siezed this opportunity to migrate to a Mac instead

The migration from Vista to Windows 7 should be smooth since the latter is an incremental release of the former.  However, the migration from XP to Windows 7 poses some of the same structural challenges outlined in my earlier post.

At the end of the day, end users care about running their applications and expect to continue to do so over the course of routine hardware and OS refresh cycles – the hardware and OS have become a commodity. The challenge for Microsoft, and the enormous market opportunity, is to provide solutions that can permit a seamless migration from XP to Windows 7 such that end users can continue to use all of their existing applications from the same desktop cost-effectively.

While the Windows 7 migration is not a dislocating event by itself, its timing coincides with the business need to move to a modern hardware and desktop OS, which encourages corporate customers to look at alternate ways of managing the desktop. The Virtual Desktop Infrastructure (VDI) vendors are viewing it as an opportunity to gain adoption for their VDI offerings – Citrix XenDesktop, Microsoft MED-V, VMWare View.

In upcoming posts, I will outline the alternative that Microsoft is offering to smoothen the upgrade path from XP to Windows 7.

Here are the Top 12 referrers to our blog over the past 3 months, the numbers of referrals are in parentheses.

1. http://pro-linux.de/berichte/ext4/ext4.html (765)
2. http://networksecuritytoolkit.org/nst/index.html (566)
3. http://dabcc.com/article.aspx?id=9653 (149)
4. http://polishlinux.org/apps/cli/ext4-defragmentation-with-e4defrag/ (111)
5. http://kakku.wordpress.com/2008/06/23/virtualbox-shrink-your-vdi-images-space-occupied-disk-size/ (101)
6. http://stumbleupon.com/refer.php?url=http://sharevm.wordpress.com/2009/01/19/most-popular-vmware-virtual-appliances-for-it-administrators/ (84)
7. http://techblog.41concepts.com/2008/03/31/shrink-your-windows-disk-image-on-wmware-fusion-mac/ (67)
8. http://thedarkmaster.wordpress.com/2007/03/12/vmware-virtual-machine-to-virtual-box-conversion-how-to/ (66)
9. http://blogs.msdn.com/heaths/archive/2005/07/30/445621.aspx (66)
10. http://prefetch.net/blog/index.php/2007/01/21/determining-file-fragmentation-on-ext3-file-systems/ (61)
11. http://virtualgeek.typepad.com/virtual_geek/2009/01/updated-homebrew-esx-hardware-list.html (52)
12. http://blog.rightscale.com/2009/01/09/amazon-launches-ec2-console/ (53)

Thank you for the referrals. Hope the content is meaningful for our readers

The compelling aspect of Application Virtualization is that it lets applications be delivered dynamically as services that can be added or removed without installation. In trying to understand the underpinnings of this technology, I found two interesting chalk talks by John Sheehan, the architect of Softricity’s SoftGrid, which was rebranded as App-V, after it was acquired by Microsoft:

1. Introduction to Application Virtualization Technology
2. Achitecture and Engineering of App-V

What is a virtual appliance?

Wikipedia defines a virtual appliance as:

a fully pre-installed and pre-configured application and operating system environment

CIO.com calls a virtual appliance:

an application is designed, certified and delivered, with its own little OS, to run as a virtual machine on your existing physical server, or to run in a VM via a “cloud computing” service like Amazon’s.

Benefits:

The allure of a virtual appliance  is the re-packaging of an application for ease of deployment and distribution

By packaging, say, a database as a virtual appliance, the software manufacturer no longer needs to be concerned about what hardware, drivers and OS version the application is being installed upon. The manufacturer’s best practices are already incorporated into the virtual machine ensuring that it is configured correctly. Complexity is reduced while reliability is improved.

• Promotes a download and deploy model – very little to no configuration necessary
• A self serve Demo/Evaluation permits the customer to try and buy without an onsite presence by the vendor.
• Pre-built applications can be configured correctly, tuned and thoroughly tested on the OS they are shipped, improving availability for the customer.
• Replacing virtual appliances is also much quicker and easier.
• The virtual appliance can even be replicated off site for disaster recovery.

This simplifies the deployment process and yields substantial development, testing and support cost benefits to the manufacturer and operational costs savings to the customer.

What is the market activity?

• VMWare has set up a Virtual Appliance Marketplace with nearly 500 virtual appliances
• Microsoft offers try and buy licenses for Pre-configured VHD’s  for Windows Server 2008, System Center Configuration Manager, SharePoint Server 2007, Exchange Server 2007, and more.that run on Windows only.
• Citrix has announced the first XenServer virtual appliance

Mayank Sharma has compiled a broad survey of virtual appliances and companies that offer them.

Business Model Challenges for Software Vendors:

There are licensing challenges :

• License management for individual activations of a virtual appliance.
• Licensing for crossVM-platform use, e.g.,  customers are not permitted to convert a pre-configured Microsoft vhd to a VMWare vmdk.
• Enforcing export license restrictions on software components packaged within a virtual appliance, e.g., if OpenSSL is packaged.

Ensuring Security and conformance with compliance standards is another challenge .

• The pre-configured virtual appliances may not run anti-virus or other security software because they were not designed to support them
• They may require certain  firewall ports to remain open, which violates the corporate standard

Licensing : a structural barrier for growth

A dominant majority of the appliances seem to involve open source software on Linux, primarily because the software licensing considerations do not pose a barrier for the early adopters. The obvious side-effect of this is that there is not much revenue tied to this market today.  Until the major software vendors, e.g., Microsoft, Oracle, SAP, etc., rationalize their licensing, the growth in unit deployments will be driven by open source stacks.

Best Practices

rPath has published Best Practices for building a virtual appliance. They are summarized below:

• No command line interaction should be required
• Appliance management should be web-based
• There must be a rollback mechanism for update failures
• The appliance must have the minimum possible install size
• The appliance must be secure by default
• There must be an automated method for updating both the appliance image and the field unit

Conclusion

It seems to me that VMWare, Microsoft and Citrix consider this technology to be strategic, i.e., they are investing in anticipation of growth and are evangelizing, although no one seems to have made any money so far. VMWare opened the Virtual Appliance Marketplace in 2006 but the downalods for their most popular appliances number a few hundred, they have not yet crossed the magical threshold of 1000 downloads. I had read somwhere that IDC had predicted  this market will be worth $680 million in 2011 prior to the economic meltdown of 2008 – that’s a respectable number.