Intro

My Proxmox VE cluster is almost one year old now, and it's been a while since I didn't update my nodes. Now is the time to move forward and bump it to Proxmox VE 9.

I'm mainly interested in the new HA affinity rules, here what this version brings:

• Debian 13 "Trixie"
• Snapshots for thick-provisioned LVM shared storage
• Fabrics feature for the SDN stack
• Better mobile interface
• Affinity rules in HA cluster

In this article, I will walk you through the upgrade steps for my Proxmox VE HA cluster supported by Ceph distributed storage.

Prerequisites

Before jumping into the upgrade, let's review the prerequisites:

1. All nodes upgraded to the latest version of Proxmox VE 8.4.

The latest version for Proxmox VE 8 is 8.4.1. My nodes are currently in version 8.3.2, hence a first update is necessary before the major upgrade.

nsure your node(s) have correct package repository configuration (web UI, Node -> Repositories) if your pve-manager version isn't at least 8.4.1.

• Hyper-converged Ceph: upgrade any Ceph Quincy or Ceph Reef cluster to Ceph 19.2 Squid before you start the Proxmox VE upgrade to 9.0.

  Follow the guide Ceph Quincy to Reef and Ceph Reef to Squid, respectively.

• Reliable access to the node. It's recommended to have access over a host independent channel like IKVM/IPMI or physical access.

  If only SSH is available we recommend testing the upgrade on an identical, but non-production machine first.

  It is also highly recommended to use a terminal multiplexer (for example, tmux or screen) to ensure the upgrade can continue even if the SSH connection gets interrupted.

• A healthy cluster

• Valid and tested backup of all VMs and CTs (in case something goes wrong)

• At least 5 GB free disk space on the root mount point, ideally more than 10 GB.

• Check known upgrade issues

Checks

Use console if possible, avoid using console from the WebGUI. Use SSH instead

Continuously use the pve8to9 checklist script

A small checklist program named pve8to9 is included in the latest Proxmox VE 8.4 packages. The program will provide hints and warnings about potential issues before, during and after the upgrade process. You can call it by executing:

pve8to9

Move important Virtual Machines and Containers

Upgrade

Update the configured APT repositories

Update Debian Base Repositories to Trixie

Add the Proxmox VE 9 Package Repository

Update the Ceph Package Repository

Refresh Package Index

Upgrade the system to Debian Trixie and Proxmox VE 9.0

Check Result & Reboot Into Updated Kernel

Post-Upgrade Validation

• Checking cluster communication (pvecm status)

• Verifying storage mounts and access

• Testing Ceph cluster health (ceph -s)

• Confirming VM operations, backups, and HA groups

• Re-enabling HA and migrating workloads back