Proxmox VE In-place Upgrade from 8 to 9

Proxmox VE 9 is officially out, bringing a new Debian base and a wave of improvements to the platform. In this post, I’ll walk through a quick, practical in-place upgrade from Proxmox VE 8 to 9, focused purely on getting an existing system upgraded with minimal effort. This is not a replacement for the official documentation, and you should absolutely read the Proxmox upgrade guide first.

⚠️ 🚨Important: Always consult and follow the official Proxmox VE 8→9 upgrade guide first:
🔗 https://pve.proxmox.com/wiki/Upgrade_from_8_to_9

Step 1 — Prepare the Node(s)

⚠️ Verify Backup and Free Space

Confirm you have tested backups of:

• Virtual Machines and Containers
• /etc/pve
• /etc/network/interfaces
• PBS backups (if used)

Ensure the root partition has at least ~5 GB free (10 GB or more recommended).

Check Current Proxmox Version

#!/bin/bash
pveversion

You need Proxmox VE 8.4.1 or newer before attempting the upgrade.

---

Step 2 — Update Proxmox VE 8 to Latest Patch

Update and install all current fixes:

#!/bin/bash
apt update
apt dist-upgrade

Reboot once done:

#!/bin/bash
reboot

Verify version again after reboot:

#!/bin/bash
pveversion

---

Step 3 — Merge Maintenance and Ceph Considerations

If you are in a cluster environment, migrate all tasks off the node you are about to update and enable maintenance mode to stop HA services:

#!/bin/bash
ha-manager crm-command node-maintenance enable <node-name>

If using Ceph:

#!/bin/bash
ceph osd set noout

This prevents data rebalancing while the node is offline for upgrade.

Also run the official Proxmox upgrade checker:

#!/bin/bash
pve8to9 --full

Resolve any issues reported before proceeding, if need to remove packages, perform the operation carefully.

One of the common error you may ran into it will be the systemd-boot package:

See the links for details: https://pve.proxmox.com/wiki/Upgrade_from_8_to_9#sd-boot-warning, otherwise, remove it using the following command:

#!/bin/bash
apt remove systemd-boot

Please run the pve8to9 --full command again to ensure no additional issues are present.

---

Step 4 — 📦Update APT Repositories for Debian & Proxmox VE 9

Proxmox VE 9 is based on Debian 13 “Trixie”, the source repository in the new deb822 style, so update the underlying Debian and Proxmox repositories:

/etc/apt/sources.list.d/debian.sources

#!/bin/bash
cat > /etc/apt/sources.list.d/debian.sources << EOF
Types: deb deb-src
URIs: http://deb.debian.org/debian/
Suites: trixie trixie-updates
Components: main non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg

EOF

Add Debian security:

#!/bin/bash
cat >> /etc/apt/sources.list.d/debian.sources << EOF
Types: deb deb-src
URIs: http://security.debian.org/debian-security/
Suites: trixie-security
Components: main non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg
EOF

Verify the the file, use command:

#!/bin/bash
ls /etc/apt/sources.list.d/

---

Add Proxmox VE 9 Repositories

Enterprise repository

#!/bin/bash
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

No-Subscription repository

#!/bin/bash
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

Verify the the file, use command:

#!/bin/bash
ls /etc/apt/sources.list.d/

---

Step 5 — 📦Update Ceph Repositories (Optional)

If using Ceph and already running Ceph 19.2 Squid, update its repository entries:

Enterprise Ceph

#!/bin/bash
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

No-Subscription Ceph

#!/bin/bash
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

Verify the the file, use command:

#!/bin/bash
ls /etc/apt/sources.list.d/

---

Step 6 — Remove Old .list Repository Files and Refresh Packages

After adding the new repositories for Debian Trixie, Proxmox 9, and (optionally) Ceph Squid, remove any remaining old Debian/Bookworm or Proxmox 8 .list files to prevent conflicts during the upgrade.

Before deleting anything, you may want to back up old repo files, in case you need to inspect them later:

#!/bin/bash
mkdir -p ~/apt-repo-backups
cp /etc/apt/sources.list ~/apt-repo-backups/
cp -a /etc/apt/sources.list.d ~/apt-repo-backups/

Run this command:

#!/bin/bash
# Review old .list in the /etc/apt/sources.list.d files first
find /etc/apt/sources.list.d -type f -name '*.list' -print

# Remove all old .list files
find /etc/apt/sources.list.d -type f -name '*.list' -exec rm -fv {} \;

# Show current sources.list
cat /etc/apt/sources.list

# remove the sources.list file
rm /etc/apt/sources.list

With all new repositories in place:

#!/bin/bash
apt update  #ensure it is from the Trixie sources are listed.

---

Step 7 — Upgrade to Proxmox VE 9

Now proceed with the upgrade:

#!/bin/bash
apt dist-upgrade

During the process you will be prompted about configuration file decisions:

Click Yes on the Configuring libc6:amd64 Prompt:

File	Suggested Choice
/etc/issue	N (Keep the current settings)
/etc/lvm/lvm.conf	Y (use new maintainer version)
/etc/ssh/sshd_config	N (Keep the current settings)
/etc/default/grub	N (Keep the current settings, unless unchanged)
/etc/chrony/chrony.conf	Y (Use maintain a version, if unchanged)

Review prompts and respond based on your customizations.

⚠️Important, also in the official documentation, if you're using UEFI mode with LVM, GRUB Might Fail To Boot, using the following commands to check:

#!/bin/bash
[ -d /sys/firmware/efi ] && echo "UEFI boot" || echo "Legacy BIOS boot"   # To check if your system are using UEFI.


# Installing the following correct grub meta-package to boot
[ -d /sys/firmware/efi ] && apt install grub-efi-amd64

# Command to check grub menu if needed: 
grep "^menuentry" /boot/grub/grub.cfg

---

Step 8 — Reboot & Verify

After the upgrade completes:

#!/bin/bash
reboot

Verify you are now running Proxmox VE 9:

#!/bin/bash
pveversion

---

Step 9 — Restore Cluster Services

If in a cluster:

#!/bin/bash
ha-manager crm-command node-maintenance disable <node-name>

If using Ceph:

#!/bin/bash
ceph osd unset noout

Verify cluster status:

#!/bin/bash
pvecm status  $ Check the Proxmox cluster status
ceph -s  # verify the Ceph cluster is in a healthy state

Repeat for each node one at a time if needed.

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Tips & Summary

• Perform the upgrade one node at a time in a cluster to maintain quorum and reduce risk.
• If using maintenance or HA, ensure all workloads have been migrated off the node before upgrading.
• Test upgrades in a staging environment if possible.
• Console access (iDRAC/iKVM) is recommended in case SSH drops.

Proxmox VE 9 introduces improvements in storage, networking, and overall system management. A careful, planed upgrade, updating repositories, and following the official checklist and repository changes — will help ensure a smooth transition from version 8 to version 9.