Until recently, most server virtualization environments were based on hypervisors from a single vendor. However, it is becoming increasingly common for virtualization administrators to manage an environment with multiple hypervisors. Factors such as mergers, acquisitions, and even budget changes have led to the adoption of competing hypervisor platforms. Although managing multi-hypervisor deployments is never easy, there are some strategies that can help things go a bit more smoothly.
Acquire a multi-platform management tool
The first thing you should do when faced with a multi-hypervisor environment is adopt a tool that will allow you to centrally manage both environments. Although a few such tools exist, none of them provide completely comprehensive management capabilities for all of the major hypervisors. Microsoft's System Center Virtual Machine Manager 2012 R2, for instance, is able to manage Hyper-V, VMware vSphere and Citrix XenServer. However, because the tool is a Microsoft product, it provides better management capabilities for Hyper-V than it does for vSphere or XenServer.
My experience has been that multi-hypervisor management tools are generally acceptable for day-to-day virtualization management. However, you may have to resort to using the native management tools (Hyper-V Manager, vSphere Client, etc.) for making infrastructure-level changes. The bottom line is multi-platform management tools are almost essential, but administrators need to be aware of any existing feature and coverage gaps.
Ensure adequate training
Proper training is also essential to the long-term success of your multi- hypervisor deployment. Admittedly, there are a lot of similarities between the leading hypervisors, but the actual management processes could not be more different. That being the case, you can't assume that just because someone is a vExpert they will be able to intuitively figure out a Microsoft or a Citrix environment. More importantly, training helps to ensure familiarity with vendor-specific best practices.
Apply policies uniformly
Another recommendation is to configure your hypervisor environment in as consistent a manner as possible. Remember, your goal is to make the management process as easy as you can. One way of achieving that goal is to adopt similar policies and configurations for the various hypervisor deployments (at least as your business requirements allow). There should ideally be as much consistency and familiarity as possible as administrators move back and forth between the two environments.
The ways in which policies can be uniformly applied vary widely depending on business requirements and on the multiple hypervisors you use. However, you may be able to adopt a common set of administrative permissions, VM naming conventions, and VM lifecycle management policies.
Plan a long term road map
One of the most important things you can do is prepare a long-term road map for your virtualization infrastructure. Start by evaluating the reasons why you are currently operating a multi- hypervisor environment. From there, you can begin formulating a plan for either long-term coexistence or for an eventual migration. In some situations, this might require you to have a discussion with software vendors so you can match your roadmap to theirs.
Recently, for example, I spoke to someone who had been operating a Hyper-V environment for quite some time. However, the organization made the decision to purchase a particular infrastructure management product, which was only available as a VMware virtual appliance. The organization therefore had to establish a small VMware environment just to accommodate the new software. My recommendation in this situation was to talk to the vendor that produces the virtual appliance and inquire as to whether the company had plans to eventually produce a Hyper-V version. It would likely be more cost-effective in the long run to eventually adopt a Hyper-V version of the software rather than maintain multiple hypervisors.
Of course, a hypervisor migration isn't always the best course of action. Suppose, for instance, an organization with a well-established VMware deployment acquires a company that has a large and complex Hyper-V deployment. It may very well be in the organization's best interest to keep the two environments separate and to leverage the existing virtualization investment than to attempt a migration.
Managing multiple hypervisors is rarely easy, but you can make day-to-day operations a lot more efficient by adopting a multi-platform management tool and by standardizing the deployments by applying policies uniformly. It is also a good idea to consider the long-term implications of operating a multi-vendor environment, and determine whether an eventual consolidation might be in the organization's best interest.