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=buster
tpl=netbsd92
tpl=obsd69
tpl=dfly621

cd /data/guests/$tpl/
ls -alF ~gns3/GNS3/images/QEMU/
#ls -alF /root/GNS3/images/QEMU/
#ls -alF ~/GNS3/images/QEMU/
qemu-img convert -f qcow2 -O raw $tpl.qcow2 ~gns3/GNS3/images/QEMU/$tpl-ready.img
chown -R gns3:gns3 ~gns3/GNS3/images/QEMU/

fortunately it remains sparse

du -sh ~gns3/GNS3/images/QEMU/*.img

Skeleton

    File / New template

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

    buster / netbsd / obsd69 / dfly621
    512 MB / 256 MB / 256 MB / 256 MB
telnet
    IMAGE-ready.img

    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