I need to update my proxmox server from 8.3 to 9.0 to get something working. I also want to checkout the new container feature in Proxmox 9.0.

Step by Step guide Link to heading

Before your start please have ssh connect so if the web pages goes done then you still have ssh connection. You can use this command

ssh root@proxmox-ip
  1. First backup everything you can. The thing you must backup is the source file for packages
 cp /etc/apt/sources.list /etc/apt/sources.list.bak
  1. Disable enterprise repo
sed -i 's/^deb/#deb/' /etc/apt/sources.list.d/pve-enterprise.list
  1. Remove the ceph repo
rm /etc/apt/sources.list.d/ceph.list
  1. Add the Proxmox 9 No-Subscription Repository
echo "deb http://download.proxmox.com/debian/pve trixie pve-no-subscription" >> /etc/apt/sources.list
  1. Update Debian Codename from Bookworm to Trixie
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
  1. Refresh APT Package List and upgrade the system
apt update && apt dist-upfrade
  1. Reboot the server
reboot

Automation Link to heading

bash script Link to heading 

#!/usr/bin/env bash
set -e

# 1. Backup Current APT Sources
cp /etc/apt/sources.list /etc/apt/sources.list.bak

# 2. Disable Enterprise Repository
# Comments out the enterprise repo to avoid subscription errors.
sed -i 's/^deb/#deb/' /etc/apt/sources.list.d/pve-enterprise.list

# 3. Remove Ceph Enterprise Repository
# Removes the Ceph enterprise repository that requires a subscription.
rm /etc/apt/sources.list.d/ceph.list

# 4. Add the Proxmox 9 No-Subscription Repository
# This enables Proxmox 9 updates without a license.
echo "deb http://download.proxmox.com/debian/pve trixie pve-no-subscription" >> /etc/apt/sources.list

# 5. Update Debian Codename from Bookworm to Trixie
# Switches the Debian base from Debian 12 to Debian 13.
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list

# 6. Refresh APT Package List
# Loads the latest package information from the updated repos.
apt update

# 7. Perform the Upgrade
# Upgrades all packages to Proxmox VE 9 and Debian 13.
# Tip: If prompted about config files, press N to keep your existing ones.
apt dist-upgrade

# 8. Reboot the Server
reboot

Ansible playbook Link to heading 

---
- name: Upgrade Proxmox 8.x to Proxmox 9 (Debian 13)
  hosts: proxmox
  become: yes
  gather_facts: no

  tasks:
    - name: Backup /etc/apt/sources.list
    # Creates a backup copy so you can revert if needed
      copy:
        src: /etc/apt/sources.list
        dest: /etc/apt/sources.list.bak
        remote_src: yes
        mode: '0644'

    - name: Disable Proxmox enterprise repository
      lineinfile:
        path: /etc/apt/sources.list.d/pve-enterprise.list
        regexp: '^deb'
        line: '#deb'
        backrefs: yes
      ignore_errors: yes  # in case the file doesn't exist

    - name: Remove Ceph enterprise repository
      file:
        path: /etc/apt/sources.list.d/ceph.list
        state: absent

    - name: Add Proxmox 9 no-subscription repository
      lineinfile:
        path: /etc/apt/sources.list
        line: "deb http://download.proxmox.com/debian/pve trixie pve-no-subscription"
        create: no
        insertafter: EOF

    - name: Update Debian codename from bookworm to trixie
      replace:
        path: /etc/apt/sources.list
        regexp: 'bookworm'
        replace: 'trixie'

    - name: Refresh APT package list and perform dist-upgrade
      apt:
        update_cache: yes
        upgrade: dist

    - name: Reboot the server after upgrade
      reboot:
        msg: "Rebooting after Proxmox 9 / Debian 13 upgrade"
        reboot_timeout: 1800