How To Run GNS3 VM on KVM [Guide]

Install GNS3 VM on KVM

The steps below will guide us on how to successfully deploy a GNS3 instance on KVM.

Original content from computingforgeeks.com - post 76060

Download the latest version of GNS3 VM image for KVM on this page.

curl -s  https://api.github.com/repos/GNS3/gns3-gui/releases/latest |grep browser_download_url  | grep GNS3.VM.KVM | cut -d '"' -f 4 | grep '\.zip' |  wget -i -

Extract the downloaded zip file to a directory in your local machine.

unzip -d gns3-vm GNS3.VM.KVM*.zip

In the command above, we have extracted the GNS3 components to a folder called gns3-vm.

The components of the extracted files are:

The KVM disk images
Script for importing the VM and starting it using QEMU.

Run GNS3 VM on KVM

The next phase will be firing up the VM. Before we can do that, we need to make sure that we have KVM installed on our host computer. Use the link below to check out how to install KVM on Ubuntu.

Install KVM Hypervisor on Ubuntu 24.04|22.04|20.04

Navigate to the folder in which we extracted the files. You should see the disk images and the script named start-gns3vm.sh.
Run the script to spin up your GNS3 VM.

cd gns3-vm
./start-gns3vm.sh

The script brings up a KVM instance and boots it up with the disk image for GNS3.

If you are accessing your KVM host over SSH, you won’t be able to use the startup script because you will run into errors. This happens because the scripts expects a GUI display available for the VM, which is not the case if you are on SSH.

The alternative is to you spin the VM directly using virt-install then access the console remotely via virt-manager or cockpit web UI. Copy the VM qcow2 disks to /var/lib/libvirt/images/:

cd gns3-vm
sudo cp GNS3\ VM-disk001.qcow2 GNS3\ VM-disk002.qcow2 /var/lib/libvirt/images

Then spin the VM using virt-install:

sudo virt-install \
  --name GNS3-VM \
  --memory 4096 \
  --vcpus 2 \
  --os-variant ubuntu24.04 \
  --import \
  --disk path=/var/lib/libvirt/images/'GNS3 VM-disk001.qcow2',format=qcow2,bus=virtio
  --disk path=/var/lib/libvirt/images/'GNS3 VM-disk002.qcow2',format=qcow2,bus=virtio
  --network network=default,model=virtio \
  --graphics vnc,listen=0.0.0.0 \
  --video virtio \
  --noautoconsole

At this point, we can reach the GNS3 VM running on KVM using the KVM network bridge.

Configure GNS3-GUI with KVM instance

The next step is to configure GNS3-GUI application to use the newly setup GNS3-VM as the server. On the Setup Wizard, choose ‘Run appliances on a remote server‘ option.