I migrated the entire k3s cluster from a flat network to a proper VLAN architecture: Server VLAN 20 for k3s nodes and services, Storage VLAN 30 for the NAS, and the existing default VLAN 1 for clients. This involved changing IPs on all VMs, updating MetalLB, reconfiguring Traefik, and recovering from an etcd quorum loss when I moved too many nodes at once.
https://blog.zolty.systems/posts/2026-02-16-vlan-migration
