Using virtual machine via vmd on OpenBSD 6.8

OpenBSD 6.8 comes with the vmm(4) hypervisor and vmd(8) daemon. Instead of installing VirtualBox or look for kvm on OpenBSD, everything is already there, a built-in virtualization solution.

Check wiki FAQ first

https://www.openbsd.org/faq/faq16.html

it lists all features, not ready features, prequisites, basic commands.

Distro

Sure run OpenBSD guest on OpenBSD host is "should just work", it's fully tested. But for Linux based OS, the options are not much:

It's a real coincidence, someone asked the question two days ago on Reddit: https://www.reddit.com/r/openbsd/comments/llscql/most_easiest_linux_distro_to_install_in_vmd/

Thanks to the answers there, I tried many but success only some:

• AlpineLinux: use "Virtual" edition https://alpinelinux.org/downloads/ "it just works", just boot on and run setup-alpine
• Debian: I used debian-10.8.0-amd64-netinst.iso, after start, type Tab, then enter console=ttyS0,115200 then enter, the text-based-curse-like UI would work.

And these failed:

• Ubuntu: ubuntu-20.04.2-live-server-amd64.iso, failed.
• NixOS: failed at phase 2/3 of systemd.
• ArchLinux: failed with error ACPI BIOS Error (bug): A valid RSDP was not found (20200925/tbxfroot-210)

Most of these default to use Video, thus must add boot parameter:

type Tab, then enter console=ttyS0,115200 then enter,

https://help.ubuntu.com/lts/installation-guide/amd64/ch05s03.html

Network

Setup pf and sysctl net.inet.ip.forwarding=1 as metioned in FAQ, NAT for the VMs

After installed, can ssh from OpenBSD host to guest via, change to your IP get from output of ip ad after installed:

ssh root@100.64.1.3 -v

Note that password login seems always fail even put correct password (or maybe Linux-based OS disabled them by default). Copy your pubkey to /root/.ssh/authorized_keys then ssh would work.

Commands

Two major important commands:

Create image

vmctl create -s 10G image.qcow2

Start VM

vmctl start \
  -i 1 \ # 1 interface
  -L \ # create interface
  -c \ # auto connect console after started
  -m 1G \ # 1G memory
  -r file.iso \ # path to ISO file (CD)
  -d image.qcow2 \ # image created above
  myvm # name of VM

vmctl status
vmctl stop ID

The start command would start and give the name temporary, after installed, create a file at /etc/vm.conf with config like:

vm "alpine" {
    disable  # disable auto start when boot
    memory 1G
    disk "/root/linux.qcow2"
    local interface
}

Result

VMs installed successfully run smoothly on vmd, low CPU usage (compare to VirtualBox on MacOS).

Have fun.