Convert a KVM guest to a GNS3 template

assuming you got GNS3 up and running already

Virtual disk

assuming you got the KVM guest template image ready already

as root to reach gns3 user directory – assuming server mode, even locally

tpl=bookworm
tpl=netbsd92
tpl=obsd69
tpl=dfly621

ls -lhF /data/guests/$tpl/$tpl.qcow2
ls -lhF /data/guests/$tpl/$tpl.img

# remote-mode
ls -alF /root/GNS3/images/QEMU/

dest=/root/GNS3/images/QEMU/$tpl-ready.img

qemu-img convert -f qcow2 -O raw /data/guests/$tpl/$tpl.qcow2 $dest
cp -i /data/guests/$tpl/$tpl.img $dest

Skeleton

    File / New template

manually create a new template
QEMU / Qemu VMs --> New

    gnu/linux   512 MB
bsd     256 MB
telnet
new image: path/to/kvm-guest-vdisk.img
copy to the default image directory? yes (not sure why it gets stuck otherwise)

tune a few things (Edit)

    general     vcups 2
general     telnet auto start console
hdd     disk interface virtio
    network     adapters 3
network type    virtio-net-pci

Resources

https://gns3.com/community/featured/how-to-configure-serial-interfac

obsd appliance

https://www.gns3.com/marketplace/appliances/openbsd

https://docs-v1.gns3.com/appliances/openbsd.html

https://github.com/GNS3/gns3-registry/blob/master/appliances/openbsd.gns3a