Installing Cumulus VX on Proxmox VE

Installing Cumulus VX on Proxmox VE

This document describes how to deploy NVIDIA Cumulus VX (Cumulus Linux 5.x) on Proxmox VE using the QCOW2 disk image provided by NVIDIA.

Cumulus VX allows you to simulate a Cumulus Linux switch using KVM.

1. Requirements

ItemDetails
HypervisorProxmox VE 7.x / 8.x
Image Typecumulus-linux-5.x-amd64-qemu.qcow2
Minimum VM Specs2 vCPUs, 2GB RAM, 6GB disk
Boot ModeSeaBIOS (Legacy BIOS) — NOT UEFI
Disk BusVirtIO or SATA

2. Download the Cumulus VX QCOW2 Image

Download from the NVIDIA Cumulus website:
cumulus-linux-5.3.1-vx-amd64-qemu.qcow2

Upload it to the Proxmox node using:

Option A — Proxmox GUI → Datacenter → Storage → Upload
or
Option B — SCP/rsync:

scp cumulus-linux-5.3.1-vx-amd64-qemu.qcow2 root@proxmox:/var/lib/vz/images/

3. Create a New VM (Empty VM First)

In Proxmox UI:

  1. Create VM

  2. Name: CUMULUS-VX

  3. OS Tab → Do NOT select any ISO

    • Set: Do not use any media

  4. System Tab

    • BIOS: SeaBIOS

    • Machine: i440fx (recommended)

    • SCSI Controller: VirtIO SCSI (default)

  5. Hard Disk Tab

    • Bus/Device: Do not create a disk

  6. CPU: 2 cores (or more depending on need)

  7. Memory: 2048–8192 MB (8GB ideal)

  8. Network: VirtIO (bridge=vmbr0)

  9. Finish creation.

Example VMID in this guide: 138

4. Import the QCOW2 Disk

Move into your image folder:
cd /var/lib/vz/images/138

Import the QCOW2 into the local-lvm storage:

qm importdisk 138 cumulus-linux-5.3.1-vx-amd64-qemu.qcow2 local-lvm

Proxmox outputs something like:

successful import disk 'local-lvm:vm-138-disk-1'

5. Attach the Imported Disk to the VM

Attach as virtio0:
qm set 138 --virtio0 local-lvm:vm-138-disk-1

Set boot order:

qm set 138 --boot order=virtio0

6. Final VM Configuration (Expected)

In Proxmox → Hardware, you should see:

Make sure to remove unused disks:

qm set 138 --delete unused0

7. Start the VM

Start from GUI or run:
qm start 138

Open the console — Cumulus should boot cleanly:

Cumulus Linux GNU/Linux
Login:

Default login:

user: cumulus
pass: CumulusLinux!

You will be prompted to change the password at first login.

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