Proxmox VE 8 to 9 Upgrade Guide

This guide provides detailed instructions for upgrading Proxmox VE 8 servers to Proxmox VE 9, based on a successful production upgrade.

Prerequisites

Before starting the upgrade, ensure:

Server backups are completed
All VMs and containers are backed up
No critical workloads are running during upgrade window
Console/IPMI access available in case of issues

Step 1: Run Pre-upgrade Check

First, run the comprehensive upgrade checker to identify any issues:

pve8to9 --full

This will check 45+ components and identify any warnings or failures that need resolution before proceeding.

Step 2: Resolve Pre-upgrade Issues

Based on the checker output, resolve common issues:

Update Available Packages

apt update && apt upgrade -y

Fix GRUB Bootloader Configuration

If you see bootloader warnings about removable EFI boot:

echo 'grub-efi-amd64 grub2/force_efi_extra_removable boolean true' | debconf-set-selections -v
apt install --reinstall grub-efi-amd64

Remove Conflicting systemd-boot Package

apt remove systemd-boot

Install Intel Microcode (Intel systems only)

Enable non-free-firmware repository and install microcode:

# Update sources.list to include non-free-firmware
echo 'deb http://deb.debian.org/debian bookworm main contrib non-free-firmware' > /etc/apt/sources.list
echo 'deb http://deb.debian.org/debian bookworm-updates main contrib non-free-firmware' >> /etc/apt/sources.list
echo 'deb http://security.debian.org/debian-security bookworm-security main contrib non-free-firmware' >> /etc/apt/sources.list

apt update
apt install intel-microcode

Step 3: Verify All Issues Resolved

Re-run the pre-upgrade checker to confirm all issues are fixed:

pve8to9 --full

You should see: TOTAL: 45, PASSED: 38, SKIPPED: 5, WARNINGS: 0, FAILURES: 0

Step 4: Configure Proxmox VE 9 Repositories

For No-Subscription Environments

Create the new Proxmox VE 9 repository in deb822 format:

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

For Enterprise Environments

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

Step 5: Remove Old Repository Files

Clean up old repository configurations to avoid conflicts:

rm -f /etc/apt/sources.list.d/pve-install-repo.list
rm -f /etc/apt/sources.list.d/pve-enterprise.list

Step 6: Update Package Lists and Verify

apt update
apt policy

Verify that the output shows only the desired repositories and no conflicts.

Step 7: Perform the Upgrade

Execute the distribution upgrade:

apt dist-upgrade

Expected upgrade scope:

~595 packages to be upgraded
~142 new packages to be installed
~59 packages to be removed
~1.2 GB additional disk space needed

The upgrade process typically takes 15-45 minutes depending on system specifications and network speed.

Step 8: Post-Upgrade Steps

Reboot the System

reboot

Verify Upgrade Success

After reboot, check the version:

pveversion

Should show Proxmox VE 9.x.x

Check System Status

systemctl status pve-cluster pveproxy pvedaemon pvestatd

Verify Storage and Services

pvesm status
pve-firewall status

Check Running VMs and Containers

qm list
pct list

Modernize Repository Sources (Recommended)

Convert old sources.list format to modern deb822 format:

apt modernize-sources

This will:

Convert /etc/apt/sources.list to /etc/apt/sources.list.d/debian.sources
Add proper GPG signatures automatically
Create backup files (.bak) for safety
Modernize other .list files to deb822 format

After modernization, clean up any unused enterprise repositories if you don’t have a subscription:

# Remove enterprise repo if you get 401 Unauthorized errors
rm -f /etc/apt/sources.list.d/pve-enterprise.sources
apt update

Final System Health Check

# Check system resources
free -h
df -h /

# Verify uptime and kernel
uptime
uname -r

# Check for any service issues
journalctl --since "1 hour ago" --priority=err

Key Changes in Proxmox VE 9

Debian 13 (Trixie) base system
Ceph 19.2.3 integration
QEMU 10.0.2 hypervisor
Linux Kernel 6.14.x with latest hardware support
Updated networking stack with enhanced performance
Enhanced security features and hardening
Modern deb822 repository format (use apt modernize-sources)
Improved container and VM management
Better resource monitoring and statistics

Troubleshooting

Common Issues

Repository Conflicts: Ensure old .list files are removed
Package Conflicts: Run apt autoremove after upgrade
Boot Issues: Verify GRUB configuration is correct
Service Failures: Check logs with journalctl -xe
401 Unauthorized Errors: Remove enterprise repository if no subscription
Sources Modernization Fails: Manually create .sources files if needed
Web Interface Inaccessible: Check pveproxy service and SSL certificates
Storage Issues: Verify NFS/CIFS mounts and permissions

Emergency Recovery

Boot from Proxmox VE installation media
Mount existing system and chroot
Restore from backups if necessary

Post-Upgrade Verification Checklist

Core System Verification

Version Check: pveversion shows Proxmox VE 9.x.x
Kernel: uname -r shows 6.14.x-x-pve or newer
Services: All core services running (systemctl status pve-cluster pveproxy pvedaemon pvestatd)
Storage: All storage pools active (pvesm status)
Firewall: Status shows “disabled/running” or as configured (pve-firewall status)
Memory/Disk: Adequate free resources (free -h && df -h /)

Repository Modernization

Sources Modernized: Run apt modernize-sources successfully
Backup Created: Original .list files backed up as .bak
Enterprise Repo: Removed if no subscription to avoid 401 errors
Update Works: apt update runs without errors

Application Testing

Web Interface: Accessible at https://your-server:8006
VM Management: Can start/stop VMs (qm start/stop VMID)
Container Management: LXC containers function (pct start/stop VMID)
Storage Access: Can create/delete disk images
Network: VMs/containers have network connectivity
Backup Jobs: Scheduled backups continue to work
Cluster: All nodes communicate (if clustered: pvecm status)
Console Access: VNC/SPICE consoles work for VMs/containers

Performance and Monitoring

System Load: Reasonable CPU/memory usage
Error Logs: No critical errors (journalctl --since "1 hour ago" --priority=err)
Hardware: Intel microcode loaded (Intel systems)
GPU Passthrough: Still functional if previously configured
Monitoring: Graphs and statistics updating properly

Notes

This upgrade path moves from Debian 12 (Bookworm) to Debian 13 (Trixie)
Ensure adequate downtime window for mission-critical environments
Consider testing on non-production systems first
Keep rescue media and backups readily available

Additional Resources

Last updated: October 16, 2025 Tested on: Proxmox VE 8.4.x → 9.0.x

Proxmox VE 8 to 9 Upgrade Guide#

Prerequisites#

Step 1: Run Pre-upgrade Check#

Step 2: Resolve Pre-upgrade Issues#

Update Available Packages#

Fix GRUB Bootloader Configuration#

Remove Conflicting systemd-boot Package#

Install Intel Microcode (Intel systems only)#

Step 3: Verify All Issues Resolved#

Step 4: Configure Proxmox VE 9 Repositories#

For No-Subscription Environments#

For Enterprise Environments#

Step 5: Remove Old Repository Files#

Step 6: Update Package Lists and Verify#

Step 7: Perform the Upgrade#

Step 8: Post-Upgrade Steps#

Reboot the System#

Verify Upgrade Success#

Check System Status#

Verify Storage and Services#

Check Running VMs and Containers#

Modernize Repository Sources (Recommended)#

Final System Health Check#

Key Changes in Proxmox VE 9#

Troubleshooting#

Common Issues#

Emergency Recovery#

Post-Upgrade Verification Checklist#

Core System Verification#

Repository Modernization#

Application Testing#

Performance and Monitoring#

Notes#

Additional Resources#