Written By: Steve Kaplan - INX
Microsoft is a huge company with a vast number of products. Licensing can be, to say the least, confusing. The virtualization environment has been particularly challenging in obtaining clarification around licensing. This is probably due, in part, to the fact that Microsoft has previously not viewed virtualization as an alternative to physical computing. We've advised our clients on licensing issues according to our best educated guess - but have been unable to get written confirmation from Microsoft.
This changed, though, in October with a 31-page white paper that Microsoft produced in order to clarify their licensing in a virtualized environment. We were pleased to see not only that all of our assumptions were validated, but that Microsoft also extended licensing benefits beyond what we expected. Unfortunately, the white paper itself tends to still be confusing at times. I've studied the paper at length along with Microsoft tech blogs, the press and Gartner opinions in order to boil down the salient information for VMware ESX Server environments.
Virtual Processor Licensing
Most press articles claim that Microsoft's former licensing policy meant that running a single instance of SQL Server on a multiple CPU ESX Server required licenses for each CPU. Our contention has always been that the Microsoft SQL Server licensing agreement clearly indicates that licensing occurs at the HAL level rather than the physical, meaning that a single instance of SQL Server utilizing only one CPU requires only one license, even if running on a multiprocessor machine. The new Microsoft licensing leaves no doubt that this is now the case:
If you run the software in virtual OS environments, you need a license for each virtual processor used by those virtual OS environments on a particular server-whether the total number of virtual processors is lesser or greater than the number of physical number of processors in that server.
What This Means for VMware Environments
This licensing benefit is particularly important for users of expensive Microsoft licenses such as SQL Server or BizTalk Server. You can run, for example, an instance of Microsoft SQL Server on a multiprocessor machine, but only have to pay for one license as long as it's set up as a single CPU Virtual Machine. Since ESX Server is so efficient at delivering virtual processor and memory resources to SQL Server, many organizations will require fewer virtual CPUs than they would have physical. This becomes even more pronounced in a dual core server environment. A company that was paying $35,000 to run SQL Server Enterprise Edition on a physical 2-CPU server may now well get by with only paying $17,500 to run a one-CPU instance on a two or four CPU dual core ESX Server and still receive similar or even improved performance.
While this type of licensing savings tends to be only a drop in the bucket compared to overall savings and cost avoidance from migrating to virtual infrastructure, it does provide some nice extra icing on the cake.
Active Virtual Machines
Microsoft has now confirmed that inactive instances of Microsoft products, i.e. running on a failover server or at a disaster recovery site, do not require extra licensing.
To help you take advantage of the deployment flexibility that VM technology offers, all products in the Microsoft Servers licensing models are licensed by running instance. The use rights no longer specify the number of times the software may be installed and used on a server. Rather, each license gives you the right to run a certain number of instances of the software on a particular server at a time.
For example, each license for Exchange Server grants you the right to create any number of instances of Exchange Server on any of your servers or storage media and the right to run one instance of Exchange at a time
What This Means for VMware Environments
This is a fantastic confirmation for virtual infrastructure users! Organizations can utilize scripting to essentially cluster servers across their SAN, but only have to pay for a single instance since the "failover" server is inactive. The same is true for the disaster recovery environment. Organizations can now have instances of their production servers running inactive at their disaster recovery sites without being required to pay extra for the licenses.
Expanded Use Rights for Windows Server 2003 R2
The new Microsoft licensing allows up to four instances of Windows Server 2003 R2 Enterprise Edition to be run in virtual OS environments on that server, while only paying for one license. Gartner Research states: "Windows Server 2003 R2, Enterprise Edition is the only edition that will allow the customer to run one instance in a physical operating system (OS) environment and up to four instances in virtual OS environments for one license fee." http://www.gartner.com/DisplayDocument?doc_cd=132810
What This Means for VMware Environments
While more expensive than the Standard edition, the ability to run up to four instances of Windows Server 2003 R2 (Enterprise) on a single physical ESX server and only pay for one license will still enable some attractive economic benefits for many organizations.
Moving Virtual Machines Between Servers
CRN's October 10 issue reports, "The Redmond, Wash.-based software giant also altered its portable licensing terms so customers can move virtual machines from one server to another without limitation, provided that the physical server is licensed for the product." http://www.crn.com/sections/microsoft/microsoft.jhtml?articleId=171204402
This sentiment is echoed by most other trade articles, and Microsoft's white paper is, in fact, not very clear on what it means now to license the targeted physical server for the product. Fortunately, Microsoft's Ward Ralston, clarifies further in a TechNet blog http://blogs.technet.com/windowsserver/archive/2005/10/10/412280.aspx:
(3) You can move active instances of a virtual instance from one computer to another without limitation . This will allow, for example, a virtual image that is stored on a SAN to be deployed to any server with available resources and licenses.
(4) To compliment the above scenario, licensing only counts towards the number of actually running virtual instances that are running. This will allow customers to store as many dormant images as needed.
What This Means
Organizations can now utilize VMotion to move virtual machines around between physical ESX servers without fear of running into licensing issues.
External Connector
Many Terminal Server / Citrix "shops" are familiar with Microsoft External Connector. It's required to enable anonymous external users to access applications via TS or Citrix.
...for products in the Server OS and Server/CAL licensing model, each EC assigned to a server allows any number of external users to access any number of instances of the server software on that server. You do not need a separate EC for each instance of the software, or for each OS environment on that server.
What This Means:
This is a welcome relief for organizations that increasingly are virtualizing Citrix over Terminal Server. An external user now does not require separate EC licenses in order to access multiple instances of Microsoft software running on a single ESX Server.
Management Licenses Licensed Per Managed Device, Not Per Managed OS Environment
Microsoft has now clarified the process of managing multiple OS environments on a device:
Each management license (e.g., OML, CML) assigned to a managed device is sufficient for any number of OS environments on that device to be managed by the server software.
What This Means
You do not need a separate management license to manage each OS environment on a Managed server. For example, even if a server is running multiple OS environments, and Microsoft Operations Manager (MOM) is separately managing each of those OS environments, you only need a single OML for the server.
Device Client Access Licenses (CALs) Licensed Per Device, Not Per OS Environment on that Device
VMware ACE (Assured Computing Environment) is a great product for enabling completely secure end-point computing. Unfortunately, the Microsoft licensing issue has always been unclear (we wouldn't even make an assumption on this one). Now Microsoft has issued some clarification:
Each device CAL assigned to a device (e.g., client device) allows any number of OS environments on that device to access the server software. You do not need a separate device CAL for each OS environment on that device
What This Means
ACE users can now confidently access a separate virtualized desktop without requiring separate CAL licensing for accessing the same server as the regular desktop OS. If, for example, both the local environment and ACE both access a Terminal Server, only one TS CAL is required. Microsoft does not clarify the licensing requirements for a client device with different operating systems accessing multiple servers. My guess is that the same licensing will apply...I will try to get further clarification from Microsoft. If the licensing doesn't apply it will open up some tricky scenarios. For instance, we have a medical ISV client who is looking to promote ACE to its customers to enable their secure access of the ISV's hosted Web application. In order to ensure that we comply device licensing rules, we could always host the Web link on a local ESX Server at the ultimate customer's site that also hosts its other important local servers.
Conclusion
While some licensing confusion still exists, Microsoft has taken great strides in easing their customer pain. Microsoft obviously sees the value of enterprise virtualization and is catering to its increasing number of clients who are insisting upon clarity and support.
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