Proxmox VE is excellent for what it is: an open-source KVM-based virtualization platform optimized for small-to-mid-size deployments. The architectural moment many teams reach is when production grows past Proxmox’s design center — multi-tenancy at scale, managed databases, AI/GPU workloads, regulated multi-customer cloud — and the operational cost of running Proxmox at that scale exceeds the licensing savings.
Cozystack is the open-source platform built for that next stage. Kubernetes-native virtualization (KubeVirt), multi-tenant control plane, managed database services, S3 object storage, GPU as a service — on the same hardware Proxmox runs on, with a different operational model.
Pairs with: Ænix Public Cloud Platform — a complete public-cloud product for hosting providers and regional clouds outgrowing Proxmox: customer portal, billing and service catalog. WHMCS billing integration (a proprietary Ænix module), multi-tenant by design, productized installer. Support tiers from $1,250 per 10 nodes per month.
When Proxmox stops being the right answer
- Multi-tenancy is required — Proxmox resource pools and ACLs delegate well inside one organisation; they are not built for untrusted customers under regulatory audit.
- Service catalog beyond VMs — managed databases, S3, K8s tenancy, GPU workloads. Proxmox is VM-focused; integrating these on top is doable but operationally heavy.
- Service-provider scale — multi-customer cloud with billing integration, self-service portal, audit per tenant.
- Production multi-cluster federation — Proxmox clusters federate; the operational model is heavier than Kubernetes.
Where Proxmox VE is genuinely better
Simplicity is a feature, and none of the tables above price it:
- One ISO, one afternoon. A working cluster with HA and a web UI, stood up by one person. Cozystack asks the team to understand Kubernetes before it understands the platform, and that is a real cost.
- Proxmox Backup Server. Incremental, deduplicated, verified backups with single-file restore, from the same vendor, in the same UI. Velero plus per-application PITR covers the same ground with more moving parts and more design.
- ZFS and Ceph built in. First-class, installable from the UI, vendor-supported. No storage architecture decision on day one.
- Subscription cost. Proxmox subscriptions are priced per CPU socket per year: the Community tier sits in low three figures, and the tiers with support tickets cost more, but all of them are a different order of magnitude from any platform engagement, ours included.
- LXC. A container that behaves like a machine is genuinely useful and Kubernetes does not offer it.
If your deployment is single-tenant, VM-mostly, and run by a small team, Proxmox is the right answer and migrating costs more than it returns. Cozystack is the upgrade path once hard multi-tenancy, a catalogue beyond VMs, or per-tenant billing enter the requirements.
What Cozystack adds vs Proxmox VE
| Capability | Proxmox VE | Cozystack |
|---|---|---|
| Compute | KVM/LXC | KubeVirt (KVM) + Kubernetes containers |
| Storage | ZFS, Ceph (community), shared storage | LINSTOR (DRBD) or SeaweedFS |
| Network | Linux bridge, SDN | Cilium (eBPF) |
| Multi-tenancy | Resource pools + role-based ACLs + auth realms | Tenant CRD, nested tenants, scoped audit |
| Managed databases | Manual install or community LXC templates | First-class: PostgreSQL, MariaDB, Valkey, Kafka, ClickHouse, RabbitMQ |
| Object storage | Manual install | First-class S3-compatible |
| GPU | Passthrough | Passthrough or NVIDIA vGPU for VMs; GPU Operator + HAMi sharing for pods |
| Self-service portal | Web UI for VM ops | Cozystack Dashboard — full multi-tenant catalog |
| Backup/DR | PBS (Proxmox Backup Server) | Velero + per-app PITR |
| Licence | AGPLv3 (open source) | Apache 2.0 (open source, more permissive) |
| Best for | SMB virtualization, labs | Multi-tenant cloud, service providers, regulated enterprise |
Cozystack is not “Proxmox but better” — it’s a different architectural target. For SMB-scale single-tenant virtualization, Proxmox remains a strong choice.
Migration path from Proxmox to Cozystack
VM image migration is straightforward — Proxmox’s qcow2 images import directly into KubeVirt’s storage. Multi-tenant model is designed rather than converted — pools and ACLs do not map onto tenants. Networking and storage layers re-architect.
Typical migration: a 14- or 28-day Platform Readiness Assessment, then 3-9 months implementation depending on scope. Details: Proxmox migration hub.
How to start
If you’re evaluating where Proxmox stops being right for your use case, start with a free architecture call.
- Cozystack vs Proxmox — head to head
- Proxmox migration hub
- Proxmox vs VMware vs Cozystack — comparison guide
- VMware alternative — for teams coming from VMware
- Private cloud consulting — broader scope
- Cozystack — the platform
Ænix created Cozystack (CNCF Sandbox project, CNCF Certified Kubernetes distribution) and co-maintains it. On top of it we offer Ænix Public Cloud Platform, Ænix Private Cloud Platform and Ænix AI Platform.