Proxmox 6 to 7 upgrade. Network no longer works.
Obviously without the network nothing works on Proxmox. No way to get in, no way to serve pages, nothing is possible except by going to the physical console and typing commands. The process is pretty simple to upgrade. You are actually upgrading to Debian Bullseye (probably from Buster). Predictable issues can crop up. The answers to those issues are not always what the developer states. And the forums and other requests for help are not typically on point because they only cover the basics. In our case we were upgrading 1 of 3 nodes in a cluster as a test. There was nothing in the documentation that stated that all nodes need to be upgraded at once. When we went through the upgrade we followed the online guide for doing…