Title: Genkernel with virtio drivers
Date: 2017-04-06
Lang: en
Tags: Gentoo

A colleague asked me to help analyze problems migrating a [Gentoo](http://www.gentoo.org) guest VM from a [Xen Server](https://xenserver.org) based host to a [Proxmox](https://www.proxmox.com) (KVM based) host. The Gentoo VM would not boot beyond the initramfs - it just died saying that the root device could not be found.

Since the VM itself boots, [Grub](https://en.wikipedia.org/wiki/GNU_GRUB) is fine. So I figured it must be a problem with the contents of the initramfs. I made sure that the virtio drivers were properly configured into the kernel - as modules.

After a lot of poking around I found [a reddit](https://www.reddit.com/r/Gentoo/comments/25fkvk/gentoo_guest_on_virtio_kvm_how_to_initramfs_via/) that mentions [genkernel](https://wiki.gentoo.org/wiki/Genkernel). I was not aware that genkernel is picky about the modules that are included into the initramfs.

In the end I did not try the approach that is suggested in the reddit. I rather compiled all virtio drivers directly into the kernel. Easier to maintain, less fiddling with genkernel. Life's good again.