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We have a physical machine that runs VMware and hosts a VM we use for SharePoint deployment testing. That machine is old and dying, and my employer's network czars are heavily pushing hosted VMs as a replacement for outdated physical servers. I was curious about whether it's possible to run VMware inside VMware, and if so, whether there are severe performance implications. We don't require extreme performance from this setup, since it's just used for SharePoint testing and the associated SQL Server is on a different box. My guess is that we can't just use the primary hosted VM for our testing because we'll want to roll back occasionally and otherwise have more control over it, and getting buy-in for that from the network folks is unlikely. Does anyone have any experience with this?

edit: I know this nesting certainly isn't the preferred option, but (1) we want the flexibility of being able to use VMware snapshots at will and (2) the network folks will not allow us to arbitrarily roll back to a previous point in time because of the potential for removing mandated security updates. My guess is that a local desktop machine running VMware Workstation might just be the way to go. The hosted option seems attractive if it will work though since it's less machine maintenance for me to deal with.

Chris Farmer
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14 Answers14

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The technical limitation with running VMware inside VMware is that VMware, Virtual PC, etc takes advantage of the Virtualization features present in modern CPUs.

If you have two or more hypervisors are both trying to control Ring 0 then there will be problems, this is something that I've encountered while trying to run both VMware and Virtual PC simultaneously on my desktop - one will error out/crash.

If your hypervisor can interact with the 'parent' hypervisor, then you'll be OK. Alternatively if the child hypervisor doesn't try to use the CPU virtualization features, or entirely emulates the CPU (such as QEMU) then you should also be OK.

Basically old-style hypervisors on old CPUs use Full virtualization (slow) which would be capable of nesting with a heavy, heavy performance hit. modern Hypervisors/CPUs use hardware assisted virtualization (near native performance) and you'd be hard pressed to find a hypervisor that is designed or capable of nested virtual machines.

Finally, I'd really advise against running dev/test VMs on the same physical server that is running production VMs. There's just too much to go wrong and security implications - you need to manage the dev/test environment and it sounds like you shouldn't have access to production environment. Likewise you probably don't want the operations team messing about with your test environment.

UPDATE: ESXi 4 now supports virtualizing itself. See this article for more information

saschabeaumont
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I've never run VMware in VMware, but I've run VirtualPC inside VirtualBox without problems, so there's no fundamental reason it shouldn't work I suppose...

It sounds to me more like you have a problem with the inflexibility of your "network czars" than any technical one. If you're a developer or QA you need a testing environment where you can fool around with outdated (and potentially insecure) versions of the OS and applications, without putting the rest of the company network at risk.

bobince
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Ex-VMware employee here.

Firstly, when you say Nested VMware I will assume you mean Nested ESXi. (You could also mean Workstation, Fusion, or Player).

Nested ESXi environments are unsupported and should not be used for production. These scenarios are not tested in QA and not guaranteed to work. In short, if you experience any kind of problem, VMware will not help you with this Nested ESXi setup.

With that said, yes you can do it and yes it does work. A lot of people use nested ESXi in their labs but not in production. Previously there were special configuration file edits that were necessary for nested ESXi to work. I have seen environments with even 3 layer nested ESXi servers (ESXi vm on and ESXi vm on a physical ESXi host). More recently there is the ESXi appliance which makes this much easier.

Have a look here: http://www.virtuallyghetto.com/2015/12/deploying-nested-esxi-is-even-easier-now-with-the-esxi-virtual-appliance.html

madacoda
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I ran into this same problem. I work at a large company where our entire infrastructure is virtual, so if you need a server you get a VMware VM. So I had a couple of Windows 2003 Server Standard Edition based Guest VM's that had 6GB of memory and 200 GB of disk space, but I wanted to run linux and a LAMP stack on them. So I tried to install VMware Workstation on one and I got an error message saying it couldn't be installed within a VM. I also tried Microsoft Virtual PC and got a similar error message. I installed Sun's VirtualBox and that installed fine, but I couldn't get the networking to work w/in the guest Ubuntu OS. My next step is to try QEMU although performance might become an issue.

pfeilbr
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You ought to have a look at Mainframes - they are Virtualised from the word go:

Hardware - runs Hypervisor Type 1 - Level 1 on this you have zVM - Type 2 Hypervisor - Level 2 on this you have zOS - your main big operating system - Level 3 and/or on this you have zLinux - Level 3 and/or on this you have zVM for testing next version - Level 3 and/ on this you have zOS for testing zVM plus zOS both at next version - Level 4

So going down to level 4 is pretty common Mind you on a Mainframe you can have 1000's of VMs running at the same time - and most sites who start using zVM/CMS and zVM/Linux usually do.

NoelG
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JFYI: I tried installing and running VMware ESXi server host(child ESXi server) as a virtual machine(on parent ESXi server) and it runs however you can not run any VMs under child ESXi server.

user1618238
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I am doing practice of VMware vSphere Data center virtualization on single Physical machine. There is VMware Workstation installed on Windows 8 OS. In VM Workstation, I have installed Windows Server 2008 OS, VMware ESXi OS and created the VMware Data center LAB. There is VMs running in LAB, and its confirm that We can user VMware in VMware. But it depends on your need, and Products which is chosen.

Patil Prasad
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You can install ESXi on VMware Workstation, it's usefull to learn ESXi, so there in no reason run VMware in VMware.

Archil Labadze
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Yes. You can run VMWare inside VMWare. Though its not officially supported, You can deploy VMs in the child ESX. I have checked for an advanced feature like PassThrough the HBA card but which was not available in child ESX, hence I could not provide a LUN from array. So in production its better to not use this. But for training and practices this can be used.

Nix
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I can see two solutions for this (three if you count a VM inside a VM which is just crazy).

  1. New hardware, which should be robust enough to handle several VM's used specifically for testing (sharpoint, etc.). In this situation your team could be given more rights without affecting non-testing VM's.

  2. Sharepoint test VM's are moved to the main VM pool and those who need access are given the ability to checkout/deploy/rollback testing resources. This could be direct through VMWare tools or through an internal project that works through a VMWare API.

This should be a joint decision between Network/Dev/Testing.

chills42
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  • I agree it sounds crazy on the surface to VM in a VM, but is it really? I've been unable to find any performance numbers of any kind. I do agree that your #1 is probably the best choice. – Chris Farmer Jan 13 '09 at 15:33
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You can do that.

You can install vmware esxi inside virtual machine of another vmware esxi.

But the performance will be very bad.

Angel M. Hernández Oliva
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Totally works.. totally can't do it other then for some kinda testing or some kind of educational purpose, because you won't get support. and from my limited experience it doesn't perform that well.

Vaedur
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Yes, you can, VMware can even detect if it's running inside of another vmware machine and warn you that VMception will cause worse performance. which it will, trust me, just try to get the version the virtual machines work best in a physical machine, as to get as much performance possible.

Becatto
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"whether it's possible to run VMware inside VMware" What?

I can run Windows with Sharepoint in a VMWare machine that's hosted somewhere.

Or, I can run Windows with Sharepoint in a WMWare machine that's actually a VMWare machine that's hosted somewhere.

Why on earth would I add a level of nesting? Why not just go with Windows with Sharepoint hosted somewhere?

You can have any number of VMWares running on a single host. Lots of different versions doing lots of different things.

Nesting them doesn't make sense.

S.Lott
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  • One issue is that we cannot arbitrarily create new VMs on the main hardware. These are hosted VMs and there is paperwork and $$$ required to get one set up, so we can't just create these as easily as on a desktop workstation. – Chris Farmer Jan 13 '09 at 15:41
  • @Chris Farmer: Nesting them still doesn't make sense. Pay the $$$'s. – S.Lott Jan 13 '09 at 17:44
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    In Red Tape Land, nesting can absolutely make sense. – csj Oct 02 '09 at 00:33
  • I hope you never have to write an emulator in Java. It sounds like the VM in the VM would make your head a splode. :) – bzlm Apr 08 '10 at 12:01
  • @bzlm: My answer has nothing to do with writing an emulator in Java. That's obvious and easy. My answer is why bother running a VM under another VM? What's the point? – S.Lott Apr 08 '10 at 13:16