FUCKUP #003: The VMs That Broke After Migration — But the Problem Was the Switch
The symptom Two Windows Server 2019 virtual machines were no longer properly reachable after they were moved to newer Proxmox hosts. The timing made the migration itself look suspicious. The VMs had moved, and their network connectivity had failed. What made it misleading Several plausible causes fit the initial symptom: differences between the old and new Proxmox hosts virtual NIC configuration bridge configuration Windows networking migration behavior the Ceph and storage context The incident happened on a weekend. The immediate operational priority was fast service recovery, so restoring service took priority over isolating each variable in the failed state. ...