In order to migrate centos to hyper-v, there is need to include hyper-v drivers to initramfs. The next command will do the task:
dracut -f --add-drivers 'hv_vmbus hv_storvsc hv_netvsc hv_utils hv_balloon hyperv-keyboard hyperv_fb hid-hyperv'
Or else system will fail to detect the disk and will fail to boot. If you see the emergency shell then it is the case.
Possible error messages:Timed out waiting for device ...
Warning: /dev/disk/... does not exist
Tested on centos 8
