Convert VirtualBox .ova to .qcow2
extract the disk image
tar -xvf junos-vsrx-12.1X47-D20.7-domestic.ova
convert VMDK to QCOW2 format
qemu-img convert -O qcow2 junos-vsrx-12.1X47-D20.7-domestic-disk1.vmdk junos-vsrx-12.1X47-D20.7-domestic.qcow2
February 2017
Ubuntu GNS3 Server with KVM support
add gns3 repository
sudo add-apt-repository ppa:gns3/ppa
update apt
sudo apt-get update
install gns3 server
sudo apt-get install gns3-server
install kvm support
sudo apt-get install qemu-kvm libvirt-bin virtinst bridge-utils cpu-checker
make sure your system supports virtualisation
kvm-ok
than you should get something like this
INFO: /dev/kvm exists
KVM acceleration can be used
then run server
gns3server --host 192.168.7.15