vQFX is not a standard Linux VM; it requires specific QEMU arguments. Standard Ubuntu or CentOS templates will fail to boot. Create an XML file (vqfx-exclusive.xml):
<domain type='kvm'>
<name>vqfx-exclusive</name>
<memory unit='GiB'>4</memory>
<vcpu>2</vcpu>
<os>
<type arch='x86_64' machine='pc-q35-6.2'>hvm</type>
<boot dev='hd'/>
</os>
<features>
<acpi/>
<apic/>
</features>
<cpu mode='host-passthrough' check='none'/>
<devices>
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2' cache='none' io='native'/>
<source file='/var/lib/libvirt/images/vqfx202r1-10.qcow2'/>
<target dev='sda' bus='sata'/>
</disk>
<interface type='bridge'>
<mac address='52:54:00:aa:bb:01'/>
<source bridge='br0'/>
<model type='e1000'/>
<address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/>
</interface>
<serial type='pty'>
<target port='0'/>
</serial>
<console type='pty'>
<target type='serial' port='0'/>
</console>
</devices>
</domain>
Critical tweaks for the exclusive image:
The vqfx202r110reqemuqcow2 exclusive image provides a complete Juniper QFX data center switch experience for development, testing, and learning without hardware. Its "exclusive" value lies in:
⚠️ Note: If you actually need modern features (e.g., EVPN Type 6, Segment Routing, 2024-era BGP), request a newer vQFX image like
vqfx-20.2R1.10-qcow2or higher. Version 11.0 is functionally obsolete but useful for legacy system emulation.
virtual switch, specifically the Routing Engine (RE) component running Junos OS version 20.2R1.10. Core Components
A functional vQFX deployment typically requires two distinct virtual machines working in tandem:
Routing Engine (RE): This image (vqfx-20.2R1.10-re-qemu.qcow2) manages the control plane, including the Junos OS CLI, routing protocols, and system management.
Packet Forwarding Engine (PFE): A separate image (often named vqfx-pfe-qemu.qcow2) that handles the data plane and actual packet switching logic. Technical Specifications vqfx202r110reqemuqcow2 exclusive
Format: .qcow2 (QEMU Copy-On-Write), optimized for use with the QEMU/KVM hypervisor.
Version: 20.2R1.10 indicates a specific maintenance release of Junos OS 20.2.
Platform: Designed for the QFX Series virtualization, used extensively in network simulation environments like GNS3, EVE-NG, or Juniper’s own vLabs. Usage Requirements
To run this specific image effectively, your virtualization host should meet the following minimum requirements:
Hypervisor: KVM-enabled Linux host or a nested virtualization environment (e.g., VMware workstation with VT-x enabled). Resources: vCPU: Minimum 1 for RE; 2+ recommended for stability.
RAM: Minimum 2GB for RE; the associated PFE typically requires 4GB+.
Connectivity: The RE and PFE VMs must be connected via a dedicated internal "fabric" bridge to communicate and function as a single switch. vQFX is not a standard Linux VM; it
For detailed configuration steps and latest features of this release, you can refer to the official Junos OS 20.2 Release Notes.
Understanding the vqfx-20.2R1.10-re-qemu.qcow2 Image In the realm of network simulation, the vqfx-20.2R1.10-re-qemu.qcow2 file is a foundational component for virtualizing Juniper Networks' QFX10000 series switches. This specific image serves as the Routing Engine (RE), the "brain" of the virtualized switch responsible for the control plane and management functions. Technical Breakdown of the Filename
The filename follows a structured naming convention used by Juniper for its virtual appliances:
vqfx: Denotes the virtual version of the QFX series switch, specifically designed for lab environments and network design testing.
20.2R1.10: This is the Junos OS version. "20.2" is the release year and series, "R1" indicates the first revision, and ".10" is the specific build number.
re: Stands for Routing Engine. In a vQFX setup, you typically need two separate virtual machines: one for the RE and one for the PFE (Packet Forwarding Engine).
qemu: Indicates that the image is optimized for the QEMU (Quick Emulator) hypervisor. Critical tweaks for the exclusive image : The
qcow2: The file extension for QEMU Copy-On-Write version 2. This is a versatile disk image format that supports thin provisioning, meaning the file only grows as data is actually written to it, saving significant disk space on the host machine. The Role of the RE Image
While physical switches integrate all components into one chassis, the virtual vQFX separates them to run more efficiently on standard server hardware.
Control Plane Operations: The RE image handles protocols like OSPF, BGP, and STP, as well as SSH access and the Junos CLI.
Management: It is where you apply all configurations. In simulation environments like EVE-NG or GNS3, you connect your management terminal directly to the RE node.
Interaction with PFE: The RE must be linked to a corresponding PFE image (e.g., vqfx-20.2R1.10-pfe-qemu.qcow2) via a dedicated internal interface, often named em1, to allow the control plane to communicate with the data plane. Usage in Network Labs
Network engineers primarily use this image to build complex topologies in virtual labs: Qemu image namings - - EVE-NG
show version
show system virtual-instance # (if multi-tenant)
show evpn instance # (if EVPN configured)
show configuration | grep exclusive # (placeholder – Junos does not have "exclusive" keyword; used here to indicate custom deployment)
Junos on vQFX is known for high idle CPU usage due to polling instead of interrupts. To fix on an exclusive image:
set system processes polling disable
set system processes traffic-management-offload
This reduces host CPU from 100% to ~15% per instance.
Before diving into terminal commands, let's break down the filename component by component, as understanding the nomenclature is critical for ensuring you have the correct image.