The hypervisor battle continues even though many in the industry believe that virtual machine software has become a commodity and it really matters little which hypervisor is selected. The companies offering virtual machine software are trying to add features and functions to their technology that will tie users into their own ecosystem of tools and add-ons, and will make their software handle larger and smaller workloads gracefully.
What is VMS?
As defined in my book Virtualization: A Manager's Guide, Virtual Machine Software is one of five different forms of Processing Virtualization. Here's a quote from the book:
Virtual machine software allows the entire stack of software that makes up a system to be encapsulated into a virtual machine file. Then a hypervisor can run one or more complete virtual systems on a physical machine. There are two types of hypervisors: A type 1 hypervisor runs on top of the physical system. A type 2 hyper- visor allows a guest system to run as a process under another operating system. Each of these systems processes as if it has total control of its own system, even though it may only be using a portion of the capabilities of a larger physical system.
The goal here is to encapsulate a complete system image and allow it to execute side by side with other virtual machines on a single physical system. Virtual machines are not aware of others executing on the same physical machine. They can be moved from one physical machine to another or from one data center to another to improve levels of workload reliability, make a workload more disaster tolerant, and provide protection from outside interference.
Companies offering VMS
Virtual Machine Software is available from the following companies and open source communities.
General purpose VMS
- The KVM community includes Red Hat, IBM, and most Linux distributions
- Microsoft offers Hyper-V, its own VMS
- The Xen community includes Citrix, Oracle, and most Linux distributions
- VMware offers vSphere, its own VMS
Special purpose VMS
If we look around a bit, we'll also discover that a number of companies are offering small, limited purpose VMS products that are sometimes described as “microvisors.” They include the following:
- Bromium is offering a vSentry, a VMS designed to isolate components of applications and the applications themselves to offer heightened levels of security and control for PC applications.
- Piston Cloud is offering Iocane, a VMS designed to secure cloud computing resources by offering them a tightly controlled, secure computing environment.
Why should we care what VMS is being used?
All of the virtual machine software products are the focus of a great deal of engineering talent. Their ability to support greater amounts of physical and virtual memory is one area of this focus. Allowing applications to execute using a number of cores or processors to improve overall performance is another – today's VMS products can present the image of having 16, 32, or even 64 processors dedicated to an application. The number and performance of networking devices is another area of intense focus. The same can be said of virtual storage available to the application. The availability of highly granular management and security are still other areas of focus.
Each supplier is trying to engage software and hardware suppliers in the hopes of creating an “all-encompassing” ecosystem which would encourage customers to select their technology over that offered by other suppliers or communities.
Enterprises today often have workloads supported by a number of different VMS products even if they had a commitment to a single product. The purchase of packaged software that was designed for another VMS is one reason this occurs. Another reason is that an enterprise may have acquired another and the other company had standardized on a dfferent product. As long as things are working, there is little incentive to change something that is at such a low level in the software stack.
It would be wise for organizations to understand that each VMS product is likely to offer a different list of benefits and restrictions. The organization could then select the best VMS product to satisfy the requirements of any given workload.