Linked clones in ESX?

[garyfritz]

I'm building a training environment that requires several VMs for each student. Due to equipment limitations I don't have infinite disk space, so storage space for the VMs is a significant issue.

In the last iteration of this class I used VMware Workstation. I was able to use linked clones to create all the VMs I needed for different parts of the class without consuming terabytes of data. Unfortunately Workstation was incapable of running the 35 simultaneous VMs I wanted to run, and performed very badly even when I scaled my model back to 21 VMs.

I tried moving the class to ESX, but I discovered ESX does (did?) not support linked clones. The non-linked VMs took up more disk space than I had available. I found workarounds that let you simulate linked clones in ESX but they were described as "unsupported" and "unreliable." I had to stick with the badly-performing Workstation setup.

A few months ago I heard a rumor that ESX would support linked clones in a release coming out in late summer or fall. I've just gone digging and couldn't find any reference to it.

Does ESX now support linked clones? If so, in what release? If not, WILL it support linked clones sometime soon?

Thanks!

Gary

[mcowger]

ESX does not currently support linked clones except as part of Lab Manager and Stage manager.

Everyone in the beta programs for future version of ESX is under NDA and cant tell you when, in ever, any given feature will come out.

Have you looked into Lab Manager? Its EXACTLY the product you are looking for.

--Matt

[weinstein5]

As Matt indicated ESX does not support linked clones - but there is hope for a future release since Lab Manager suppports linked clones and it runs on top of ESX -

[garyfritz]

Hm. So Lab Manager DOES provide a linked-clone facility on top of ESX. I read through the Lab Manager description and I'm not entirely clear if it is really a good match for what I need. Here's what I'm doing:

I'm building a training series for a blade environment. Each class has 14 students, broken into 7 teams. For various parts of the class I have labs that require VMs for different functions: infrastructure pieces like domain controllers and SQL servers, compute resources, etc. As I currently use it, early parts of the class deliver VMs with pre-installed OS's, and the students practice installing and configuring a complete solution. In later parts of the class I deliver fully-configured VMs with all infrastructure installed, and they do more advanced exercises. The advanced section in particular needs a set of 3-5 VMs.

Creating all these VMs is a #@#% of a lot of work. There is probably a better way to do it, but for the last class I created a master VM with a fully-patched OS install, then made 7 clones and manually configured each of them for hostname, IP, domain, etc etc. Then I did a similar process for the fully-configured systems.

Does Lab Manager streamline that process, or should I just use sysprep or something similar to customize the clones?

[TomHowarth]

Currently if you need linked clones on ESX you have to purchase either Lab Manager or Stage Manager. So yes ESX does support Linked Clones, but only with a additional licensed product, an alternative that could be of use to you is to use thinprovisioned disks for your XP Guests, these would only take up the actual disk space needed for the OS and Application installation. so you could have a 20GB image but only physically have 8GB on storage.

but as to when ESX will support linked clones natively you are unlikely to get an answer until the next version comes out VMware are not very good at sharing their Product Roadmap.

Tom Howarth

VMware Communities User Moderator

[mcowger]

Lab manager would allow you to create/build you master VM, and then it would deal with all the networking etc, and you wouldn't have to sysprep or change a thing on ANY VM.

--Matt

[garyfritz]

Thin provisioning -- that would require me to store the VMs on a separate disk, correct? ESX is installed on one disk, and that's VMFS, but thin provisioning requires NFS?

[garyfritz]

mcowger, that sounds excellent. I'm wondering if it gives me the control I want, though. I was setting fixed IPs on the VMs so the students could access them remotely. Does Lab Manager let you do that, or give you some good way to find out where the VMs are? I was also joining each team's VMs into that team's domain -- can Lab Manager handle that?

[mcowger · Accepted solution]

Lab Managermakes each LAB its own little thing, so each team could have a set of machines all prejoined - no manual intervention required.

You wouldn't need fixed IPs, ESX/LM handles the 1:1 NAT translation for you.

--Matt

[garyfritz]

Great. I'll look into Lab Manager for this next turn. Thanks for your help!

[esloof]

Running multiple virtual machines on one VMDK

I was playing around with my VDM2/VDI setup that was still present on my laptop since my VDM2 presentation at the Dutch VMUG. I'm running Workstation 6 and have installed ESX 3.0 as a virtual machine. Within ESX 3.0 I created one base Windows XP virtual machine and added two empty virtual machines without a virtual disk. Since I created a small VMFS I placed the Windows XP virtual machine in snapshot mode and added the virtual disk from this virtual machine as an existing disk to the other two virtual machines. I added the base disk as an independed nonpersistent virtual disk so the changes of my shadow virtual machines are discarded when I power off or revert to a snapshot. Besides an IP address conflict all three machines are running fine. In the images you can see the snapshot file and the REDO files of my shadow virtual machines. This technique could same me a lot of VDI-VMDK disk space in the first place, but what about the Windows XP license, it's only installed once......

[Dutch VMUG|http://www.ntpro.nl/blog/uploads/vmdisk2.jpg]

Dutch VMUG

[Dutch VMUG|http://www.ntpro.nl/blog/uploads/vmdisk1.jpg][Dutch VMUG|http://www.ntpro.nl/blog/uploads/vmdisk2.jpg]

[Dutch VMUG|http://www.ntpro.nl/blog/uploads/vmdisk3.jpg]

Dutch VMUG

Dutch VMUG

[garyfritz]

Interesting. I was told you couldn't run ESX on top of Workstation so I never tried it. Obviously I was told wrong.

But did you intend this as an answer to my question? I'm not quite sure how it applies...

[esloof]

My posts shows you which technique is used to create linked clones.