SUPER old post, I know, but I am running into this issue as well.
I am migrating one VM (CentOS 7, FreePBX) from a KVM VM to a Hyper-V server. I used the conversion tool "qemu-img" which worked great for another Windows workload I converted.
I did not run the command as you noted in the post before the conversion. so now I am stuck with a boot error:
Warning /dev/s7_freepbx/root does not exist
Warning /dev/s7_freepbx/swap does not exist
I booted into rescue mode with a recovery DVD/Image. I pressed 1 to continue. It told me "Your system has been mounted under /mnt/sysimage. I pressed return to drop into a shell.
I tried the command below.
mkinitrd -f -v --with=hid-hyperv --with=hv_utils --with=hv_vmbus --with=hv_storvsc --with=hv_netvsc /boot/initramfs-$(uname -r).img $(uname -r)
I got the error:
dracut: Cannot find /usr/lib/dracut/dracut-init.sh
So I typed "chroot /mnt/sysimage" and tried the command again.
and got the error below