minimalist installation of OpenBSD on the apple m2 using qemu

OpenBSD_on_Apple_M2_QEMU.md

OpenBSD on Apple M2 with QEMU

Minimalist installation of OpenBSD on the apple m2 using qemu

Ingredients

• Apple M2 running macOS Monterey 12.5.1
• QEMU version 7.1.0
• OpenBSD 7.1 arm64

Installation

1. install QEMU with Homebrew brew install qemu, also possible with MacPorts
2. Write a script with execute permissions chmod +x qemu_aarch64_install_openbsd.sh for installing the image.
   • Download the OpenBSD installation image
   • Create an image of the OpenBSD drive
   • Getting the edk2-aarch64-code
   • Installing

#!/bin/sh -
  
curl https://ftp.fr.openbsd.org/pub/OpenBSD/7.1/arm64/miniroot71.img -o miniroot71.img 
qemu-img create -f qcow2 obsd_aarch64.qcow2 32G

qemu-system-aarch64 \
    -M virt \
    -cpu host \
    -accel hvf \
    -smp 4 \
    -m 4096 \
    -nographic \
    -bios /opt/homebrew/share/qemu/edk2-aarch64-code.fd \
    -drive file=miniroot71.img,format=raw,if=virtio \
    -drive file=obsd_aarch64.qcow2,format=qcow2,if=virtio \
    -netdev user,id=mynet0,hostfwd=tcp::7922-:22 -device virtio-net,netdev=mynet0

rm miniroot71.img 

3. Follow the OpenBSD installation program, please notice the remarks at the end of this document:

4. when the installation is done, pkill qemu-system-aarch64

Running OpenBSD with QEMU

like this:

qemu-system-aarch64 \
    -M virt \
    -cpu host \
    -accel hvf \
    -smp 4 \
    -m 4096 \
    -nographic \
    -bios /opt/homebrew/share/qemu/edk2-aarch64-code.fd \
    -drive file=obsd_aarch64.qcow2,format=qcow2,if=virtio \
    -netdev user,id=mynet0,hostfwd=tcp::7922-:22 -device virtio-net,netdev=mynet0 

Remarks

• there is a problem with the DNS if the network interface (vio0) is on autoconf so is better configure it manually, have a look at QEMU's User Networking, for instance IPv4 would work on 10.0.2.15/24 and 10.0.2.2 gateway.

• alternatively a full image install71.img instead of miniroot71.img would work.

• for the lazy asses, like me, it is possible to do autoinstall(8) with an install.conf on your localhost like this one:

  System hostname = fugu
  IPv4 address for vio0 = 10.0.2.15    
  Default IPv4 route = 10.0.2.2
  DNS nameservers = 1.1.1.1 8.8.8.8
  Password for root = RootsPassword
  Setup a user = hugo
  Password for user = HugosPassword
  Public ssh key for user = ssh-ed25519 AAA...318C [email protected]
  What timezone are you in = Europe/Helsinki
  Which disk is the root disk = sd1
  Location of sets = http 
  HTTP Server = ftp.fr.openbsd.org
  URL to autopartitioning template for disklabel = http://10.0.2.2/openbsd-pgdb.disklabel 
  

  also possible to define the disk partition adding openbsd-pgdb.disklabel on your localhost like this one:

  /           0.3G
  swap        2M        10%
  /altroot    0.3G
  /tmp        120M-4G   8%
  /var        3G        13%
  /usr        0.9G-3G   5%
  /usr/local  3G-7.5G   10%
  /home       9G-*      45%