Upgrading from Proxmox VE 8 to Proxmox VE 9: a step-by-step guide

Introduction

#

Proxmox VE 9.0 was released on August 5, 2025, gaining a solid foundation built on Debian 13 “Trixie” and Linux kernel 6.14.8-2. In this article, we’ll go through the process of upgrading Proxmox 8 to 9 (Proxmox 8 to 9 upgrade) step by step - from checking compatibility to the final apt dist-upgrade command. This version marks a significant step forward in virtualization, storage, and network infrastructure capabilities.

1. Updated kernel and base system

#

• Moving to Debian 13 “Trixie” provides up-to-date packages, improved security, and compatibility with modern hardware: PCIe 5.0, NVMe, new chipsets.
• Linux kernel 6.14.8-2 is optimized for modern CPUs and network interfaces.
• Updated versions of QEMU 10.0.2 and LXC 6.0.4 are available, improving VM migration, isolation, and cgroup v2 support. The old cgroup v1 is no longer supported.

2. Storage and snapshots

#

• Support for LVM snapshots on thick-provisioned shared storage (iSCSI, Fibre Channel), which allows creating snapshots with minimal disk overhead and rollback without external tools.
• ZFS 2.3.3 is enabled with support for RAID-Z expansion - you can add disks to a RAID-Z array without downtime.
• Ceph storage is now deployed by default on Ceph Squid 19.2.3, with LZ4 compression enabled by default and improved performance for multi-user scenarios. By the way, for a home cluster, Ceph is often overkill - I covered this in more detail in a separate article.

3. Network infrastructure and SDN

#

• SDN Fabrics let you build routable overlay networks between nodes (OpenFabric, OSPF) without external switches - with support for spine-leaf and full-mesh topologies for Proxmox and Ceph clusters.
• The new proxmox-network-interface-pinning tool allows binding MAC addresses to stable names like nic0, nic1, etc., and automatically adjusts the configuration when NICs are renamed after updates.

4. HA, placement policies, and mobile UI

#

• New HA affinity rules let you define resource (VM/CT) placement across nodes or groups to minimize latency or increase fault tolerance. If your cluster isn’t set up yet - see the Proxmox clustering guide.
• A new mobile interface, built on Rust (the Yew framework), provides convenient management from a smartphone browser: VM management, HA tasks, monitoring, etc.

5. Interface, usability, and vulnerability removal

#

• Dark mode by default - the interface now starts in the dark theme; the light theme is available if explicitly chosen by the user.
• Improved display of errors, notifications, and logs; fixed issues with the UI, the OIDC window, and ISO template loading - especially in the web interface and backup job notifications.
• GlusterFS support removed: if you use GlusterFS, you need to migrate to Ceph, ZFS, or NFS before upgrading.

6. Compatibility and migration

#

• Containers on cgroup v1 (CentOS 7, Ubuntu 16.04) are not supported - it’s recommended to migrate to a modern OS beforehand.
• NVIDIA GRID/vGPU users require the GRID 18.3+ driver (version 570.158.02 or newer), compatible with kernel ≥ 6.0. Without it, vGPU support will be broken.

7. Commands from the video

#

Running the pve8to9 checklist script

pve8to9 --full

If no problems are found, proceed to the upgrade.

Updating APT repositories

First, let’s update the current configuration to the latest package versions on the current release.

apt update
apt dist-upgrade
pveversion

Updating the Debian base repositories to the Trixie version

Update the lists for both the enterprise and regular repository.

sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/pve-enterprise.list

Adding Proxmox VE 9 package repositories

First, update the enterprise repository data.

cat > /etc/apt/sources.list.d/pve-enterprise.sources << EOF
Types: deb
URIs: https://enterprise.proxmox.com/debian/pve
Suites: trixie
Components: pve-enterprise
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

Now the same thing, but for normal people.

cat > /etc/apt/sources.list.d/proxmox.sources << EOF
Types: deb
URIs: http://download.proxmox.com/debian/pve
Suites: trixie
Components: pve-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

Updating the Ceph package repository

First, update the enterprise repository.

cat > /etc/apt/sources.list.d/ceph.sources << EOF
Types: deb
URIs: https://enterprise.proxmox.com/debian/ceph-squid
Suites: trixie
Components: enterprise
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

Now for us mere mortals.

cat > /etc/apt/sources.list.d/ceph.sources << EOF
Types: deb
URIs: http://download.proxmox.com/debian/ceph-squid
Suites: trixie
Components: no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

Updating the repository data

apt update

Upgrading the Proxmox kernel

apt dist-upgrade

Conclusion

#

Proxmox VE 9.0 is an important step forward: a new stable base on Debian 13, powerful storage capabilities (ZFS, LVM, Ceph), flexible SDN settings, HA placement control, and a modern mobile UI. However, before upgrading, pay attention to container requirements, network configuration, and vGPU compatibility.

Also on this topic:

#

• Proxmox cluster: setup, QDevice, and mixed hardware in nodes
• Merging local-lvm and local in Proxmox
• Installing via Cloud-Init in Proxmox