work / case
Re-Platforming On-Prem: ESXi & Untangle → Proxmox & OPNsense
Took ownership of the on-premise infrastructure and migrated it off commercial virtualisation and firewalling onto open-source Proxmox and OPNsense — the foundation every other workload now runs on.
Problem
The organisation’s on-premise estate ran on commercial, licensed virtualisation and edge networking — VMware ESXi for the hypervisor, Untangle for the firewall and edge. It was costly, it tied the environment to vendor licensing, and the layer underneath everything else had no clear owner. This is the substrate the whole estate depends on: the Kubernetes nodes, the GPU hosts, and the storage all sit on top of it, so leaving it un-owned and un-modernised put a ceiling on everything built above.
Approach
Took ownership of the on-premise substrate and ran the commercial-to-open-source migrations end to end, as part of a broader push toward open-source adoption and a Windows-to-Linux direction across the environment:
- Hypervisor — VMware ESXi to a Proxmox cluster covering compute, storage, and networking, cut over without service loss.
- Edge & firewall — Untangle replaced by OPNsense for the network edge.
- Storage — ZFS and Ceph underneath, providing the resilient block and pooled storage the workloads above sit on.
The work was done as live migrations against a running estate, not a greenfield rebuild — moving guests, storage, and the edge across with the things on top of them still serving.
Outcome
The result is a Proxmox cluster — compute, storage, and networking — that is now the foundation the Kubernetes platform, the GPU inference pool, and the storage tier all run on. The hypervisor and edge are open-source and owned end to end, off commercial licensing, and the cutovers happened without service loss to the workloads above. It also gave the portfolio its one genuinely brownfield piece: taking over a messy, licensed estate and modernising it in place, rather than standing something new up on a clean slate.