Upgrading to Proxmox VE 9

I faced a couple of hiccups while upgradeing from 8.4 to 9.0. Luckily, no data loss occurred, but the downtime was longer than I was expecting.

Prerequisites

Be sure to run pve8to9 --full before committing to an upgrade. This command runs a checklist and gives warnings about potential problems on your setup.

For more details: https://pve.proxmox.com/wiki/Upgrade_from_8_to_9#Actions_step-by-step

Incomplete apt dist-upgrade

Here was my first problem. I ran the upgrade through SSH, and when it came to updating the SSH server, I got disconnected. Immediately, my server rebooted. When it came back up, I couldn’t re-connect and had to check its actual display output. First of all, the network didnt work. When I tried running ifreload -a, I ran into an error. After reading around, someone suggested running apt --fix-broken install. That revealed a lot of broken packages, which were able to be reinstalled.

With that in mind, it is HIGHLY RECOMMENDED to do this upgrade directly on your server’s console rather than SSH, as the wiki already suggests.

Network Interface Name Changes

I had a hard getting networking back online. While I already knew about the interface name changes, I didn’t realize they would instantly break networking on getting the server back up. Running pve-network-interface-pinning generate and editing /etc/network/interfaces based on the output resolved the network issues.