<disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='writeback' io='threads'/> </disk> Even with the exclusive tag, users run into issues. Here is how to solve them. The "Boot Loop" Trap Symptom: The VM restarts every 30 seconds. Solution: The vQFX kernel panics if it detects less than 4096 MB RAM. Ensure your Libvirt XML has <memory unit='MB'>4096</memory> . The "Missing IFD" Trap Symptom: You run show interfaces terse and see only fxp0 and dsc . Solution: The exclusive QCOW2 might be configured to expect SR-IOV. Edit the bootloader:
# Check the format and virtual size qemu-img info vqfx202r110reqemuqcow2.exclusive Should show format: qcow2 and virtual size: 10 GiB (or similar). The actual disk usage might be only 1-2GB due to sparse allocation. Step 2: Create a Copy (Preserve the Original) The "exclusive" image is your gold master. Never boot it directly. Use a backing file.
In a ContainerLab topology file ( .clab.yml ):
<domain type='kvm'> <name>vqfx-exclusive</name> <memory unit='GB'>6</memory> <vcpu placement='static'>2</vcpu> <os> <type arch='x86_64' machine='pc-q35-6.2'>hvm</type> <boot dev='hd'/> </os> <devices> <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/images/vqfx-leaf-01_disk.qcow2'/> <target dev='vda' bus='virtio'/> </disk> <!-- Management Interface --> <interface type='bridge'> <source bridge='br0'/> <model type='virtio'/> <target dev='vnet0'/> </interface> <!-- Data Plane Interface --> <interface type='bridge'> <source bridge='br1'/> <model type='virtio'/> <target dev='vnet1'/> </interface> </devices> </domain> virsh define vqfx.xml virsh start vqfx-exclusive virsh console vqfx-exclusive Warning: The "exclusive" image may boot faster than standard images, but still expect 2-3 minutes for the Juniper CLI to appear. Log in with root (no password).
<vcpu placement='static'>2</vcpu> <cputune> <vcpupin vcpu='0' cpuset='2'/> <vcpupin vcpu='1' cpuset='3'/> </cputune> Because this is a lab environment, you can sacrifice safety for speed.
Happy virtualizing.