How do you upgrade Proxmox VE 8 to Proxmox VE 9 when Home Assistant is running on the same server? In this step-by-step homelab walkthrough, I take my Proxmox 8.4 host through the major version upgrade and check that Home Assistant starts again on Proxmox 9. If the Proxmox 8 support warning has appeared in your dashboard, this video shows the process I followed and the problems I had to fix along the way.
I start with backups: a Home Assistant backup, copies of my virtual machines and LXC containers, and an off-host copy in case the upgrade goes wrong. Then I check the installed PVE version, bring Proxmox VE 8 fully up to date, and look at the Debian and Proxmox package repositories. The repository changes move the system from Debian Bookworm to Debian Trixie before the full Proxmox VE 9 upgrade.
You’ll see me run the Proxmox 8-to-9 upgrade checker, shut down my Home Assistant VM, and investigate the warnings on my machine. Those included a system boot package warning and missing Intel microcode firmware. I show the repository correction I needed for non-free firmware, rerun the checks, and begin the full upgrade. If your host uses an AMD CPU or has different storage, boot or repository settings, your warnings and fixes may be different.
I also cover the prompts that appear during the package upgrade, what to do if you see errors before rebooting, and the checks I make after the first Proxmox 9 boot. That includes starting Home Assistant, reviewing backups, and checking attached hardware such as USB devices. If you need to reinstall from scratch and restore a backup, the linked Proxmox 9 and Home Assistant installation video shows that route.
This is my real upgrade, not a one-size-fits-all command list. Read the official upgrade guidance for your setup, make tested backups before changing repositories, and do not reboot through unresolved errors. I’ll share the command list through the newsletter when it is ready.
Written guide: https://www.onporpoise.co.uk/wp-content/uploads/2026/09/WrongWords-On-Porpoise-Proxmox-8-to-9-Upgrade-Guide.pdf
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Back up your Proxmox VMs and containers off the host: https://youtu.be/-yML36Kgzv8
Fresh Proxmox 9 and Home Assistant installation: https://youtu.be/fkievT0ciIk