The Proxmox Virtual Environment (Proxmox VE) is one of the most popular virtualization platforms in the corporate world, enabling efficient management of virtual machines, containers, networks, and storage. With the release of Proxmox VE 9.0, system administrators can now take advantage of significant improvements in performance, security, and advanced features.
This guide will show you how to upgrade from Proxmox VE 8.x to Proxmox VE 9.0 in a simplified way while following best practices to avoid issues. These instructions are suitable for both small-scale home labs and large data centers using Bare Metal Servers and high-availability clusters.
Why upgrade to Proxmox VE 9.0?
- Updated base system: Debian 13 “Trixie” with Linux kernel 6.14.
- Networking improvements with SDN Fabrics and support for advanced topologies.
- Enhanced snapshots for LVM thick-provisioned storage.
- Revamped mobile interface and overall security and stability improvements.
Important tips before upgrading
- Perform the upgrade using direct console access or via iDRAC/IPMI to avoid disconnection issues.
- Ensure at least 10 GB of free space on the root (
/) partition before upgrading. - In clusters, upgrade one node at a time.
Step-by-step: Upgrading from Proxmox VE 8 to 9.0
1. Perform a full backup
Before any upgrade, it is critical to back up all virtual machines, containers, and configuration files, such as /etc/pve and /etc/network/interfaces. This ensures that if something goes wrong, you can quickly restore your environment.
2. Run the compatibility checker
Proxmox provides a built-in tool to analyze your current setup and identify potential issues before the upgrade:
pve8to9 --full
Fix all warnings before proceeding to ensure a smooth upgrade process.
3. Update to the latest Proxmox 8 release
The upgrade to Proxmox VE 9.0 requires you to be running at least Proxmox VE 8.4. Run the following commands:
apt update && apt dist-upgrade
pveversion
4. Update Ceph (if applicable)
If your cluster uses Ceph, ensure it is upgraded to the Squid (19.2) release before moving to Proxmox VE 9.0.
5. Update repositories to Debian 13
Proxmox VE 9.0 is based on Debian 13 “Trixie”. You will need to update your APT repositories:
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/pve-enterprise.list
If you use the no-subscription repository, make sure the file is updated to “trixie”.
6. Perform the upgrade
Now upgrade the entire system to Proxmox VE 9.0:
apt update && apt dist-upgrade
Once complete, reboot your server to start with the new kernel.
7. Verify the upgrade
After rebooting, confirm the version with:
pveversion
Test your VMs, containers, and networking features to ensure everything is functioning correctly.
