vmctl – https://man.openbsd.org/vmctl
vmd – https://man.openbsd.org/vmd
Start by downloading the desired OpenBSD version you want to run. In my case I wanted to run OpenBSD 6.2 which is EOL.
I found a Swedish repo that has all OpenBSD versions available so I downloaded it from here:
I had some issues booting only from the install62.iso so I downloaded the bsd.rd and booted from it and used the iso just to install all sets.
vmctl create -s 12G openbsd62.immg
vmctl start -m 4G -L -i 1 -b bsd.rd -r install62.iso -d /home/abc/vms/openbsd62.img -c openbsd62
After the install finishes you can boot directly from you virtual disk.
vmctl start -m 4G -L -i 1 -d /home/abc/vms/openbsd62.img -c openbsd62