How migrate my PVS golden image from Hyper-V to Xenserver 8 ?

[Andy Vanderbeken]

We have an old batch of HP DL380 G7 servers running Hyper-V that are due replacement by new HP DL380 G10 servers which I'm currently testing in POC. Since I would like to use vGPU in the future hardware design I have to migrate away from Hyper-V to Xenserver 8 but my I cannot install the xentools on my PXE-booted PVS golden image in private mode and when I try going the long way (convert the VHD to vmware and then to XVA and import it) the console stalls after "booting from HD...success".

 

So how does one migrate a PVS golden image from Hyper-V to Xenserver 8 successfully ?

[Andy Vanderbeken]

hey all,

 

I was able to solve everything. Here's the relevant update and solution for anyone interested now and in the future:

 

The bluescreens on Xen VM's when going into windows mode turned out to be indeed exactly what I wrote in previous update. Refer to that section for details. The way to work around it was indeed going the long way of converting all the way to Xen VM disk, make the changes to it as a local attached Xen VM HD in order to be able to register the network adapter and then convert all the way back to PVS on windows. This brings us to the following questions and answers:

 

 1. Is there an equivalent script for Xenserver or how can I create VM's or single network adapters inside them that always use the exact same identity ?

 

=> none needed since both Xenserver (and VMware) automatically retain the same ID when cloning a machine as opposed to Hyper-V which creates -by default- a new (different) identity for each new VM where the build needs to be launched on each VM at least once and for each VM a network adapter will be detected in windows and added into the golden image (with a different number) unless you use the powershell scripting to set their identities equal at Hyper-V machine creation time.

 

2. How can I convert my PVS golden image .VHD to a working VM machine on Xen ?

 

=> Apparently I found a bug in Xenserver conversion where it wrongfully converts EUFI machines into BIOS machines causing them to stall at boot. In addition Xenserver -unlike VMware- does not allow you to just go change from BIOS to UEFI in the settings of the VM. It can only be chosen at VM creation time.

 

So the solution here is as creative as the bug: Shut down your newly created (by the xenconversion) machine, detach the disk, create a new VM but UEFI this time and finally reattach the converted vm disk. After that the image boots properly as any classic locally attached hard disk would allowing you to start detecting the network adapter and registering it into the golden image build. After that you can cleanup whatever you like (hidden hardware etc) or not at all because everything works just as fine without.

 

3. How can I convert my finalized Xen VM disk (with all the changes inside it) back to a .VHD on my provisioning server ?

 

=> perform the initial one-time "imaging wizard" included with PVS just like you would with the first time virtualization of a physical hardware server. Since the network adapter for this batch of virtual Xen VM's is now known in the registry you can now and ever more boot into this VM directly off PVS in private mode to include any future changes and updates to hardware (except the newtwork card)

[Alan Lantz]

From what I can tell 1707/1709 are just benign messages and don't have anything to do with the fact

your VM blue screens later.  Could just be whatever combination of softwares you are using at present.

Quite frankly I'm old school at present, XenApp 6.5, XenServer 7.1 and PVS 7.1.3.

 

--Alan--

 

 

 

[Alan Lantz]

When you are upgrading your XenTools in private mode are you booted from a hard disk or the pvs image? You can't upgrade XenTools 

while booting on the image. You would need to reverse image to a hard drive so the drivers can be updated that does the PVS over

the network part. Another way to do it is if you have NFS available which is quicker since you don't need to reverse image.

 

--Alan--

 

[Andy Vanderbeken]

so I have a PVS server running Windows Server 2016 which holds and streams the .VHD files to Gen2 Hyper-V virtual machines running Citrix virtual apps. So I copy the latest .VHD (our golden image) to a Hyper-V server and mount it as a locally attached HD and boot from it. Then I install the Xen VM tools and get both successfully installed as reply as well as "Installation failed" in the Windows event viewer. In the add/remove program the management agent  shows up as installed.

 

Next I shut down that Hyper-V machine, copy the modified .VHD file (with the newly installed Xen tools inside it) back over to the PVS server and now use it to stream towards a newly created Xen VM in PVS private mode (=editable HD) but this Xen VM machine just bluescreens after loading windows. Some screenshots below:

 

https://imgur.com/a/oxHs6Br

 

[Alan Lantz]

I think I would uninstall XenTools and PVS Target Device software, then reinstall XenTools and PVS Target Device Software.

I don't like that error message you are getting,  that doesn't seem normal to me.  Using Hyper-V should be another way

to keep from having to reverse image.

 

--Alan--

 

 

 

[Andy Vanderbeken]

Ok, I uninstalled both in that order and rebooted.

 

Next I reinstalled only Xentools and got the same dual error/success message with the following log details:

 

 

[Tobias Kreidl]

Any tools on Hyper-V should be first uninstalled before the export. We have honestly just gone successfully the other way around (XS to Hyper-V) with some VMs, which has its own set of quirks.

[Andy Vanderbeken]

Guys,

 

thx for your replies and ideas. I think I just had a 'flashback of enlightenment'. This bluescreen phenonema I haven't seen for such a long time since everything has been cookie cutter stable for years here but it suddenly hit me that I have had this 7 years ago in the beginning as well. It happens typically when the network adapter's identity in windows is not known inside the golden image build so once it leaves PXE boot phase and reaches windows phase, windows loses the very lifeline it's streaming it's own HD content (=PVS) from and so it crashes.

 

I remember now that initially on windows Hyper-V I had this as well and whenever I created new VM's I had to attach the golden image .VHD once to that machine and boot it once into windows to make this new machine's network adapter identity known and registered in the windows registry. This operation had to be done for each new VM at least once since each VM creates by default it's own unique network adapter identity which has to become known in the golden image build.

 

Later I eliminated the need for this step by using a powershell script on the windows Hyper-V host machines which modifies the VM's by adding/replacing a VM network adapter to it with a specific predefined identity that is always the exact same one for each new VM I create or for each existing one I modify. After this one-time-change operation all existing and future VM's always used (and still do up till today) the exact same network identity in the registry which was already previously known in the golden image and therefore no longer causes bluescreens.

 

So I guess when switching platform from Hyper-V to Xenserver I'm back to square 1 and will have to go the long way again at least once which means fully convert my PVS golden image .VHD to an actual Xen attachable VM HD, boot into windows  at least once to register the network adapter into the registry and then convert back to PVS golden image .VHD

 

so this leads me to the following questions:

 

1. Is there an equivalent script for Xenserver or how can I create VM's or single network adapters inside them that always use the exact same identity ?

2. How can I convert my PVS golden image .VHD to a working VM machine on Xen (all my attempts so far don't boot passed bios!) and then back to PVs .VHD

 

[Alan Lantz]

I've never went from Hyper-V to XenServer, so I'm not sure. I would think making your VM a template would keep all of that info the

same across the pool regarding nics.  For your golden image I'm not sure, I would just expect it to work or at least work well enough.

You may have to do an OS repair on it to get it to boot properly.

 

--Alan--