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.
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 hypervisrolauchtype 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.