After a lazy friday and some try and distroy with my test Hyper-V cluster. I needed to do a startup repair with my Hyper-V testcluster. After that I encountered a funny surprise, when I tried to startup my virtual machines.
They were telling me they are not able to start because my Hypervisor was not running.
In the first step I thought “Ok could be possible that VT is disabled in BIOS”. That was possible because I made some Firmware and BIOS updates during the session and my old collegues from Dell like to joke and to enable and disable BIOS features during updates. So I checked BIOS. OK … everything fine.
I restarted my host and check the services. No, everything fine here either.
After that I did a few minutes research via web and what did I found? An article from Ben Armstrong himself, encountering the same issue.
So what was the reason why my VMs do not want to start? As you all know, when you startup a Hyper-V host, you don’t see the Hyper-V on your desktop, you see the management OS. Which means, you have something like a VM running, which manages the Hypevisor below it. What happens when you do a startup repair? You recreate the boot storage and link it directly to the installed operating system. The issue is, the startup repair don’t know that you use a Hypervisor. Which means, it doesn’t set the parameter to startup the Hypervisor first bevor it starts the management OS.
Th fix this, you need to do some easy steps.
1. Start a command promt (cmd.exe) as administrator
2. Type bcdedit /set hypervisorlauchtype auto
3. reboot your system
If you use dual boot or something, you need to specify the bootloader identifier. How that works, is shown in a blog from Keith Combs.