Josef “Jeff” Sipek

Installing Debian under FreeBSD's bhyve

This weekend I tried to move my work dev vm to a slightly beefier vm host. This meant moving the vm from kvm on OmniOS to bhyve on FreeBSD 12.1. After moving the disk images over, I tried to configure vm-bhyve to use them as-is. Unfortunately, grub2-bhyve fails to boot XFS root file systems with CRC support and there was no good way to convert the disk image to get it to boot via UEFI instead (to avoid grub2-bhyve completely). So, I decided to simply reinstall it.

In theory, this shouldn’t have been too difficult since I had the foresight to have /home on a separate virtual disk. In practice, I spent several hours reinstalling Debian Buster over and over, trying to figure out why it’d install and reboot fine, but subsequent boots wouldn’t make it past the EFI firmware.

It turns out that Debian tries to make multi-booting possible and puts its EFI binary into a non-standard location. That combined with bhyve not persisting EFI variables after shutdown results in any boot after the the first poweroff not even trying to look at the Debian-specific path.

This is not a Debian bug, but rather bhyve’s EFI support being incomplete. The easiest way around this is to copy the Debian binary into the standard location immediately after installation. In other words:

# cd /boot/efi/EFI
# mkdir BOOT
# cp debian/grubx64.efi BOOT/bootx64.efi

That’s all that’s needed. The downside to this is that the copy will not get automatically upgraded when grub gets an update.

For completeness, here are the relevant bits of the vm’s config:

loader="uefi"
graphics="yes"
cpu="6"
memory="1G"
network0_type="virtio-net"
network0_switch="public"
zfs_zvol_opts="volblocksize=4096"
disk0_dev="sparse-zvol"
disk0_type="virtio-blk"
disk0_name="disk0"
disk1_dev="sparse-zvol"
disk1_type="virtio-blk"
disk1_name="disk1"

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