Install GNS3 VM on Proxmox

These were the steps I needed to install GNS3 VM on Proxmox (KVM/Qemu) with ZFS datastore.

This assumes you have Proxmox already installed and running, and that nesting is working. See here for more information about enabling nesting. To verify that everything is OK:

root@proxmox:~# cat /sys/module/kvm_intel/parameters/nested
Y

# its also recommended that you have apicv enabled/working
root@proxmox:~# cat /sys/module/kvm_intel/parameters/enable_apicv
Y

On the host, we need to create the VM itself, download the GNS3 KVM image, import it, and then boot the VM.

# create a new VM
qm create 2021 \
  --cores 24 \
  --cpu host \
  --ide2 none,media=cdrom \
  --memory 65536 \
  --name gns3 \
  --net0 virtio,bridge=vmbr0,firewall=1,tag=102 \
  --net1 virtio,bridge=vmbr0,firewall=1 \
  --net3 virtio,bridge=vmbr0,firewall=1 \
  --numa 1 \
  --onboot 1 \
  --ostype l26 \
  --scsihw virtio-scsi-single

# find the URL for the latest KVM VM file
gns3_url=$(curl -s https://api.github.com/repos/GNS3/gns3-gui/releases/latest \
  | grep -E 'browser_download_url.*GNS3.VM.KVM.*\.zip' \
  | head -n1 | cut -d '"' -f4)
curl -L -o GNS3.VM.KVM.zip ${gns3_url}
unzip GNS3.VM.KVM.zip

# then we import the disks
qm disk import 2021 "GNS3 VM-disk001.qcow2" ssd-storage-vm --target-disk scsi0
qm disk import 2021 "GNS3 VM-disk002.qcow2" ssd-storage-vm --target-disk scsi1

# then we re-scan the disks to get the proper size added
qm disk rescan --vmid 2021

# add to boot order
qm set 2021 --boot order='scsi0;ide2'

# then we should be able to start it
qm start 2021