Proxmox6 on Debian10 Buster Error
First thank you very much for your nice script!!!
I used it to install 3 Servers from Hetzner to create a Cluster.
See my Error on Proxmox Forum: https://forum.proxmox.com/threads/local-node-address-cannot-use-ip-it-must-be-configured-exactly-once-on-local-node.58628/
Solution for your script: Deactivated the systemd/network or simple delete the entry on /etc/systemd/network/10-mainif.network