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ESX on ESX -- Support Topics and Thoughts

During this week's VMware Communities Podcast, nested ESX came up with a lot of feedback. The user community seems to demand more from VMware than what is available for this practice. The concept is simple: VMware's current products technically allow ESX to run as a virtual machine. This is a great tool for testing, but is officially unsupported by VMware and is a performance no-no for production-class virtualization workloads.

Setting it up is very easy. VMware employee Eric Gray provides the how-to for this topic on his VCritical blog. Like many other administrators, this is one of the only ways to set up test environments to play with new features of vSphere without allocating large amounts of hardware. Couple this with a virtual machine that functions as an iSCSI target, such as the Openfiler storage device, you can craft a 'datacenter in a box' with shared storage and multiple hosts.

The issue here is that what does VMware want to offer as an official stance for this practice? It is an unsupported configuration, but everyone does it for certain test configurations. In fact, VMware had a special build of the Lab Manager product to provision ESX as a virtual machine to support lab environments at VMworld. While we will never see that as an official guest operating system for Lab Manager or other products, it begs the question: What is the support direction on nested ESX?

During the podcast, it was clear that VMware is contemplating what to do with this feature. My opinion is that a limited support statement can be the only real option for this practice. This limited support statement could be limited to not relying on memory overcommit for the guest ESX hosts and forbidding production virtual machines to be run as guests within or alongside a virtualized ESX host. It will be interesting to see what comes of it, but don't expect anything quick, as there are more important things to tackle.

If you haven't used this feature, it is a great training tool. It is definitely worth the effort to take the time to make a few ESX hosts and a vCenter Server system all as virtual machines to use as a training environment. It is much less riskier than performing the same experiments on other environments.

What is your expectation of how VMware could issue a support statement for nested ESX? Share your comments below.

Posted by Rick Vanover on 11/19/2009 at 12:47 PM


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