The management of virtualized IT environments has become the latest technology issue due to the added burden of managing physical and virtual machines. In addition, each machine needs network and storage resources, and they may be part of a greater virtualized environment leveraging I/O virtualization, infrastructure virtualization, application virtualization and grid computing as well as umbrella management software orchestrating the various components into action.

There are a number of virtualization solutions which individually provide great flexibility, but a tradeoff of management complexity emerges, especially when these solutions are used together. It is useful to have a framework to think about these capabilities and map them to what you might need in your data center. We propose the following virtualization stack:

Server Virtualization:

Let's start at the beginning with an analogy of physical servers and a family residence to illustrate the power of server virtualization.

Server Virtualization is somewhat like moving from a home into a condo. If you own ten physical servers in your data center and want to consolidate down to one physical server, server virtualization software allows you to do just that. Companies including VMware, Xen/Citrix and Microsoft all provide solutions that allow a physical server to run multiple operating system instances and resulting families of applications. IBM, Oracle, Red Hat, Sun Microsystems, and Symantec are all invested in the open-source Xen hypervisor project.

For many companies, server virtualization has been the first big step into data center virtualization. It put VMware on the map with their IPO in August 2007, and has yielded cost savings and consolidation benefits over non-virtualized environments. When you enable multiple virtual servers and their associated applications to be consolidated onto fewer physical servers, you can more efficiently leverage a smaller number of machines, resulting in decreased expenses

Infrastructure Virtualization:

While server virtualization's hypervisors allow for a single physical machine to host multiple virtual machines, infrastructure virtualization reaches beyond the server into the data center resources outside of the control of server virtualization solutions.

Infrastructure Virtualization's emergence as a category is an acknowledgement by the industry that servers (virtual and physical) are not stand-alone resources, but rather require the leverage of network and storage resources from throughout greater data center.

Infrastructure Virtualization software products on the market today include Scalent Systems V/OE and Unisys's uAdapt. The purpose of Infrastructure Virtualization is to ensure that a server is given its required network and storage resources as needed based on the company’s business requirements and strategy. The solutions support existing bare-metal servers running Windows, Linux, and Solaris as well as full hypervisors such as VMware ESX, Xen, and Microsoft Hyper-V – with their VM load.

One effect of deploying Infrastructure Virtualization in your environment is that bringing a server on-line can be coordinated against the automated provisioning of network and storage resources to support that server. Boot storage can be allocated for diskless hosts and virtual network connectivity (VLANs) can be dynamically created to enable appropriate servers to connect with each other. This frees data center managers from having to pre-provision static associations of storage and network to servers, and breaks down silos of resources into freely available pools as needed.

Comparing server versus infrastructure virtualization reveals that the two solutions provide distinct and complementary functionality in the data center. Going back to our original analogy, server virtualization creates condos out of servers, and infrastructure virtualization dynamically moves families into and out of the appropriate units, and sets up the utilities required for occupancy, in real-time - connectivity to the network and storage. Depending on the number of physical and virtual servers that you manage, you probably need both server virtualization and infrastructure virtualization.

I/O virtualization:

I/O Virtualization consolidates the number of physical I/O connections to a given server, and also allows I/O and multiple virtual connections to tunnel through to network and storage resource across a consolidated physical infrastructure. The promise of I/O virtualization includes condensing network and storage connectivity with fewer physical cables to manage, fewer network interconnect cards deployed, and fewer switch ports consumed for the same amount of computer power.

Players in this space include Nuova, 3leaf, and Xsigo, and there is additional software specific to each solution which assigns SAN and network connectivity back to a given server. From an administrative standpoint, the physical layer becomes much easier to manage with fewer cables while the management of the virtualized connectivity to given machines becomes more complex as the virtual resources increase.

I/O virtualization complements server virtualization and infrastructure virtualization by aggregating the path to network and storage resources so that fewer components need to be touched overall. Using the condo analogy, I/O virtualization ensures that when the utilities leading to the complex become overloaded, certain tenants get priority use of those resources.

Infrastructure Virtualization software dynamically provisions a new I/O resource when bringing up a machine, and provides coordination between server virtualization and virtualized I/O resources.

Application Virtualization:

Gaining momentum but not widely deployed yet, application virtualization technologies help package, store, and distribute end-user software in an on-demand fashion across a network. This goes hand-in-hand with many of the standardized web services initiatives making waves in the tech world today.

Virtualized applications use a common abstraction layer, which defines a protocol, allowing them to communicate with one another in a standard messaging format. Thus, applications can invoke one another in order to perform requested functions. A virtualized application is not only capable of remotely invoking requests and returning results, but also ensuring that the application's state and other data are available and consistent on all resource nodes executing the application across a grid.

Application Virtualization vendors include Citrix Presentation Server, Microsoft SoftGrid, AppStream, and DataSynapse, to name a few. These solutions can run incompatible applications side-by-side at the same time, allow applications to run in environments that do not suit the native application, and improve overall security by isolating applications from the operating system. It may surprise you to find that application virtualization consumes fewer resources than deploying individual applications into separate virtual machines.

Again, Application Virtualization is complementary to the other forms of virtualization, running at the application layer on the others' virtualized infrastructure and OS.

Data Center Orchestration:

Data center orchestration provides an overarching category for coordinating the deployment of resources with the service level required by the business. If you're interested in learning more about data center orchestration, or want to learn more about how to gain efficiency in your data center via Infrastructure Virtualization, come talk with us!

Alana Achterkirchen, Director of Marketing, April 28, 2008

Labels: Scalent Systems infrastructure virtualization