You've got an Ubuntu Server box sitting under your desk or in a rack somewhere, and you keep seeing that Proxmox VE is "based on Debian." So naturally you're wondering: can you just add Proxmox on top of the Ubuntu install you already have, the same way you'd apt install any other package? No wiping, no reinstalling, no downtime.
It's a reasonable question. Ubuntu and Debian share a lot of DNA — same package format, mostly the same commands, a lot of the same documentation even applies to both. Unfortunately, the honest answer here is no, not reliably, and trying it usually costs you more time than just doing it the right way. Let's go through why, and then walk through the path that actually works without losing your data.
What You Will Learn
- Why Proxmox VE's "runs on Debian" installation method doesn't carry over to Ubuntu
- What actually happens if you try it anyway
- How to back up an existing Ubuntu Server before wiping it
- The real, supported way to get Proxmox VE running on that same hardware
- How to test Proxmox VE inside your current Ubuntu install first, without touching the host
- Common errors people hit during the migration and how to fix them
What Is This Feature?
Proxmox VE isn't an application you install into an existing Linux distribution. It's a full server operating system — a customized Debian install with its own kernel, its own management daemons (pvedaemon, pveproxy, pvestatd), and its own storage and networking stack layered on top. When you install it from the official ISO, you're not adding software to Debian, you're getting a Debian base that Proxmox has already built and configured for virtualization.
Proxmox does publish a second method: installing the proxmox-ve package on top of an existing plain Debian server (Proxmox VE 9 targets Debian 13 "Trixie"). That's the method a lot of people confuse with "you can add Proxmox to any Linux box." It works because Debian's package versions, kernel ABI, and default network tooling (ifupdown) match exactly what the Proxmox packages expect.
Ubuntu doesn't match that expectation, even though it's downstream of Debian. It ships its own kernel builds, its own patched versions of core packages, and — this is the big one — netplan instead of the traditional /etc/network/interfaces setup Proxmox's networking stack is built around. Point the Proxmox repository at an Ubuntu system and run the install, and you'll get a mix of conflicting dependencies, a kernel that doesn't have the right modules loaded for KVM and ZFS the way Proxmox needs, and a network configuration that Proxmox's web interface won't manage correctly.
Why Would You Use It?
The motivation is almost always the same: you already have a working Ubuntu Server with data on it, and reinstalling from scratch feels like a hassle, or a risk, or both. Maybe it's hosting a few Docker containers you don't want to rebuild. Maybe you just don't want to deal with re-cabling and reconfiguring a machine that already works.
That's a fair instinct. I'd feel the same way about a box I'd already tuned to my liking. But in this specific case, fighting the package manager to force Proxmox onto Ubuntu will burn more hours than a clean install plus a data restore — and you'll end up with a system that's harder to support later, because you're the only person who's ever seen that particular combination of packages. When something breaks at 11pm, the Proxmox forums and documentation assume a stock install, not your hybrid one.
Prerequisites
Before you touch anything, get these lined up:
- A USB flash drive, 8 GB or larger, that you don't mind erasing
- A second computer to download the ISO and write the USB drive
- The Proxmox VE ISO from the official downloads page at proxmox.com
- An external drive, NAS share, or second machine with enough free space to hold a full backup of your Ubuntu server's data
- A note of your current network settings — static IP, gateway, DNS, and the interface name (run
ip ato check) — since you'll need to recreate them - Physical or remote (IPMI/iDRAC/iLO) access to the machine's boot menu
If this server is doing anything production-important, plan the migration for a maintenance window. The whole process — backup, wipe, install, restore — usually takes somewhere between 45 minutes and two hours, depending mostly on how much data you're moving and how fast your backup destination is.
Step-by-Step Tutorial
Step 1: Back up everything on the Ubuntu server
Don't skip this even if you're fairly sure you don't need the data. If you're running Docker, note which containers and volumes exist first with docker ps -a and docker volume ls. Then copy the important directories to your backup location:
rsync -avz --progress /home /etc /var/lib/docker user@backup-host:/mnt/backups/ubuntu-server/For a quick full-directory archive instead, tar works fine:
tar czf /mnt/backup-drive/ubuntu-backup.tar.gz /etc /home /var/lib/docker /optAdjust the paths to match whatever actually matters on your system — config files in /etc, application data, and any custom scripts you've written.
Step 2: Download and verify the Proxmox VE ISO
Grab the ISO from the official Proxmox downloads page. Once it's downloaded, check the SHA256 checksum against the value posted on the same page:
sha256sum proxmox-ve_9.0-1.isoIf the hash doesn't match, download it again — a corrupted ISO is one of the more common causes of installer freezes later.
Step 3: Write the ISO to your USB drive
On Windows, Rufus (in DD mode) handles this well. On macOS or Linux, find the correct device with lsblk first — you want the whole disk, like /dev/sdb, not a partition like /dev/sdb1 — then write it with:
sudo dd if=proxmox-ve_9.0-1.iso of=/dev/sdb bs=4M status=progress conv=fsyncDouble-check that device path. Get it wrong and you'll overwrite the wrong drive with no warning.
Step 4: Boot the installer and wipe Ubuntu
Plug the USB into the target server, enter the boot menu (usually F11, F12, or Esc depending on the hardware), and select the USB drive. Choose Install Proxmox VE from the menu. When you reach the disk selection screen, pick the drive that currently has Ubuntu on it — this is the point where that install gets erased, so make sure your backup finished successfully before you continue.
Step 5: Set your network and finish the install
The installer will ask for a hostname (use a fully qualified one, like pve1.homelab.local), a management IP, gateway, and DNS server. Use the values you noted down in the prerequisites step so the machine keeps the same address on your network. After the install finishes and the box reboots, log in to the web interface at https://your-server-ip:8006.
Step 6: Restore your data
Depending on what you were running, this usually means creating a VM or LXC container and pulling your backed-up data back in with rsync, or reinstalling the applications fresh and copying over just the config and data directories. If you were running Docker directly on the Ubuntu host, the cleanest path is usually a Debian or Ubuntu VM inside Proxmox with Docker reinstalled, rather than running Docker on the Proxmox host itself.
Not ready to wipe anything yet? Test it nested first
If you want to see what Proxmox VE actually looks like before committing your hardware to it, you can run it inside a VM on your current Ubuntu box using KVM:
qemu-system-x86_64 -enable-kvm -m 4096 -smp 2 -cdrom proxmox-ve_9.0-1.iso -boot d -drive file=pve-test.qcow2,format=qcow2This gives you a throwaway Proxmox VE instance to click around in. It's genuinely useful for getting familiar with the interface, but nested virtualization like this isn't something you'd run in production — treat it strictly as a preview.
Commands Explained
| Command | What it does |
|---|---|
ip a | Lists network interfaces and their current IP addresses, so you can record your existing configuration before wiping it |
rsync -avz | Copies files while preserving permissions and timestamps (-a), showing progress (-v), and compressing data in transit (-z) |
sha256sum | Calculates a checksum of a downloaded file so you can confirm it matches the official value and wasn't corrupted |
lsblk | Lists block devices (drives and partitions) attached to the system, used here to identify the correct USB device before writing to it |
dd | Copies raw data byte-for-byte — in this case, writing the ISO file directly onto the USB drive to make it bootable |
qemu-system-x86_64 | Launches a KVM-based virtual machine directly from the command line, useful for a quick nested test without setting up a full hypervisor |
Common Errors
"Unable to locate package proxmox-ve" — happens when you add the Proxmox Debian repository to an Ubuntu system's sources.list. Ubuntu's package index doesn't include Proxmox packages, and even if you point it at the Debian repo directly, dependency versions won't line up with what Ubuntu ships.
Installer hangs at "Auto-installation" or partitioning — usually caused by leftover LVM or RAID metadata from the old Ubuntu install that the installer is trying to parse. This is more common on machines that previously ran Ubuntu with LVM-based partitioning.
No network after the fresh install — the interface name on the new install (commonly something like enp3s0) may not match what Ubuntu called it, especially if Ubuntu's netplan was using a different naming scheme. Check /etc/network/interfaces against ip a output post-install and correct the bridge port if needed.
"No bootable device found" after wiping — usually means the old GRUB entry is still referenced in the BIOS boot order. Enter the BIOS boot menu and manually select the new EFI boot entry, or clear old boot entries if your firmware allows it.
Troubleshooting
If the installer won't even boot from your USB drive, disable Secure Boot in the BIOS first — this trips people up more than almost anything else on newer hardware, since Ubuntu handles Secure Boot signing differently than the Proxmox installer does.
If old partitions or LVM volumes are still showing up during install even after selecting "wipe disk," boot a Linux live USB and run wipefs -a /dev/sda (replace with your actual disk) before starting the Proxmox installer again. That clears filesystem and RAID signatures that the installer's own wipe step sometimes misses.
If your restored VMs can't reach the internet after migration, check that the bridge (usually vmbr0) is actually attached to the correct physical NIC — on multi-NIC servers it's easy to bridge the wrong port during a fresh install, especially if the interface names shuffled around compared to your old Ubuntu setup.
Best Practices
Keep your Ubuntu backup around for at least a week or two after the migration, not just until the restore looks fine. Problems with missing config files tend to surface once you actually start using the server day to day, not during the initial check.
Write down your old network configuration before you wipe anything — IP, gateway, DNS, VLAN tags if any. It takes two minutes and saves you from guessing later.
Verify the ISO checksum every time, even if you've downloaded it before. A bad download is a common, boring cause of installer weirdness that's easy to rule out early.
If the server has more than one drive, consider installing Proxmox on a smaller dedicated drive and keeping the old Ubuntu drive intact (just disconnected) until you're confident everything's working. That gives you a fallback that doesn't depend on your backup being perfect.
Frequently Asked Questions
Can I add the Proxmox repository to Ubuntu and install it that way?
You can add the repository, but the install will fail or leave you with a broken, unsupported system. The official apt-based method only targets plain Debian, not Ubuntu.
Will I lose my data if I install Proxmox VE?
Yes, installing Proxmox VE wipes the target disk. That's exactly why the backup step at the start of this guide isn't optional.
Can I dual-boot Ubuntu and Proxmox VE on the same machine?
Technically you could set up a dual-boot menu, but it defeats the purpose of running a hypervisor — Proxmox needs to own the hardware to manage VMs and containers properly, and a server that's only running one OS at a time isn't doing much virtualizing.
Can I still run Ubuntu after switching to Proxmox VE?
Yes — just as a guest. Create an Ubuntu Server VM inside Proxmox and it runs exactly like it did on bare metal, just with Proxmox managing the hardware underneath it.
Is there any official Proxmox support for Ubuntu hosts?
No. Proxmox's documentation and support channels assume either a fresh ISO install or the Debian-based apt install method. Ubuntu isn't one of the supported base systems.
Conclusion
The short version: Proxmox VE and Ubuntu Server can absolutely coexist on the same hardware, just not in the way you were probably hoping. A fresh install from the official ISO, paired with a proper backup and restore, gets you there in under two hours for most homelab-sized servers, and you'll end up with a system that matches what every guide and forum post out there assumes you're running. That match matters more than it sounds like — it's the difference between finding an answer in five minutes and spending an evening debugging a setup nobody else has.