Cozystack vs VMware — head-to-head comparison for the post-Broadcom era

Open-source Cozystack (a CNCF project we create and maintain) Ænix Platform, the supported commercial distribution Aenix builds, operates and migrates it.

Cozystack vs VMware is a head-to-head comparison for organizations planning a VMware (VCF) exit after Broadcom’s pricing changes. Cozystack is an open-source (Apache 2.0) cloud platform built on Kubernetes that runs both virtual machines and containers through KubeVirt, with Cilium (eBPF) networking, LINSTOR or SeaweedFS storage, and native multi-tenancy via a Tenant CRD. Unlike VMware’s per-CPU subscription model, Cozystack has no licensing fees — cost is hardware plus a chosen support tier. Aenix, the team behind Cozystack (a CNCF project), provides the productized Ænix Platform and migration services, typically reaching a positive cumulative cost position by the end of Year 2. It suits IT leaders evaluating sovereign, vendor-neutral alternatives to vSphere, NSX, vSAN, and vCloud Director.

Quick facts

  • What it is A head-to-head comparison of Cozystack and VMware Cloud Foundation for teams planning a post-Broadcom VMware exit.
  • License Apache 2.0 (no per-CPU / per-core licensing)
  • Status Cozystack is a CNCF project (Sandbox since 2025-02-28; Incubating expected late summer 2026)
  • Who it's for IT leaders, CTOs, and infrastructure architects evaluating alternatives to vSphere, NSX, vSAN, and vCloud Director.
  • Architecture KubeVirt runs VMs and containers on one Kubernetes API; Cilium (eBPF) networking; LINSTOR/DRBD or SeaweedFS storage; Tenant CRD multi-tenancy.
  • Migration timeline Cohort-based and aligned with VCF subscription expirations — typically 7-10 months for under 100 VMs, up to 16-25 months for 500-2000 VMs.
  • Commercial offering Aenix sells the productized Ænix Platform plus services; tiers from Basic ($1,250/mo, 10 nodes) to Enterprise (custom).

You’re considering a VMware exit. The destination shortlist includes Cozystack. This page compares the two head-to-head — what’s the same, what’s different, what migration costs, what runs better on each.

For broader VMware-alternatives evaluation, see VMware alternatives listicle. For the focused vendor recommendation, see VMware alternative. This page assumes you’re already considering Cozystack specifically.

Pairs with: Ænix Public Cloud Platform if you sell cloud to customers, or Ænix Private Cloud Platform if you run it for your own organisation. Which side of that line you are on post-VMware decides it.


Architecture comparison

VMware (VCF)Cozystack
LicenseSubscription onlyApache 2.0 (open source)
ComputevSphere / ESXiKubeVirt on Talos
StoragevSANLINSTOR or SeaweedFS
NetworkNSXCilium (eBPF)
Multi-tenancyvCloud DirectorTenant CRD
Service catalogvRealize / AriaApplicationDefinition + Cozystack Dashboard
Backup/DRSite Recovery ManagerVelero + S3 + PostgreSQL PITR
GPU for VMsNVIDIA vGPU on vSphereNVIDIA vGPU + KubeVirt
Air-gapSupported (extra licensing)Supported (no extra cost)
Ops modelBroadcom support plus a large partner and ISV channelÆnix advisory + GitOps PR review; no cluster access required
Cozystack
Apache 2.0Tenant CRD multi-tenancy
one Kubernetes API
VMs and containers
KubeVirt on Talos
networking and storage
Platform services
Cilium (eBPF)LINSTOR or SeaweedFS

Where Cozystack is genuinely better

  • Pricing — no per-CPU / per-socket subscription. Hardware + chosen Ænix tier.
  • Multi-tenancy — Tenant CRD is native; vCD is bolted-on legacy.
  • Container workloads — Cozystack is Kubernetes-native, containers and VMs coexist on one platform. Tanzu is OpenShift-style add-on for VMware.
  • Sovereignty — open source on customer hardware with customer-controlled keys.
  • Vendor neutrality — no Broadcom-style pricing pressure on roadmap.

Where VMware is genuinely better

Not a courtesy paragraph. These are real gaps, and an architect will find them in week one.

  • Two decades of operational maturity. DRS, Storage DRS, Fault Tolerance, Enhanced vMotion Compatibility, Storage vMotion between arrays, vVols. KubeVirt has live migration and a working scheduler; it does not have the same depth of automated placement and rebalancing, and it has not been beaten on by as many people for as long.
  • The hardware compatibility list. VMware certifies servers, HBAs, NICs and firmware combinations, and a vendor will support you on a listed configuration. Cozystack runs on commodity hardware, which means you own that qualification.
  • The backup and DR ecosystem. Veeam, Commvault, Rubrik, Zerto and Site Recovery Manager all speak VADP natively. Velero plus per-database PITR covers the same ground with different tools, and any runbook, retention policy or audit evidence built on the VMware ecosystem is rewritten.
  • Third-party and ISV certification. Application vendors certify against ESXi. Some will not answer a support call about a workload running on KubeVirt, whatever the technical merits.
  • Established procurement and integration. ServiceNow, Ansible, and the internal tooling built around vCenter over ten years is real, working investment.

If your team is deep on vSphere, renewal economics are tolerable, and no sovereignty or multi-tenancy requirement is pushing, “stay and tune” is the correct answer and we will say so.


Migration timing

Estate sizeAssessmentImplementationTotal
<100 VMs14 days6-9 months7-10 months
100-500 VMs28 days9-15 months10-16 months
500-2000 VMs28 days15-24 months16-25 months

Cohort-based migration; aligned with VCF subscription expirations.


Cost trajectory

VCF pricing is quote-driven and non-public, so there is no honest single number to print here. What the shape of the model looks like for a 200-VM estate:

  • Year 1 — the remaining VCF subscription runs in parallel with assessment, platform build, migration labour and an Ænix support tier. Cost goes up before it goes down.
  • Year 2 onward — hardware refresh and depreciation plus an Ænix support tier, with no per-CPU meter.
  • Net cumulative position — in the engagements we have modelled, typically positive by the end of Year 2 and clearly positive by Year 3. Your renewal quote, hardware age and staffing decide it, which is why the number is computed in assessment rather than claimed here.

Model your own inputs with the VMware TCO comparison, where every price carries a source and a date.



Ænix is the team behind Cozystack (CNCF Project), and we offer Ænix Platform — our commercial productized offering based on Cozystack.

Frequently asked questions

How does Cozystack differ from VMware Cloud Foundation?

VMware is a subscription-only stack (vSphere/ESXi, vSAN, NSX, vCloud Director). Cozystack is Apache 2.0 open source built on Kubernetes: KubeVirt for compute, Cilium (eBPF) for networking, LINSTOR or SeaweedFS for storage, and a native Tenant CRD for multi-tenancy. There is no per-CPU or per-socket licensing.

How long does a VMware to Cozystack migration take?

It depends on estate size and is cohort-based, aligned with VCF subscription expirations. Estates under 100 VMs typically take 7-10 months total, 100-500 VMs take 10-16 months, and 500-2000 VMs take 16-25 months, including assessment and implementation.

When does the cost case turn positive after leaving VMware?

In the engagements we have modelled for a 200-VM estate, the net cumulative position is typically positive by the end of Year 2 and clearly positive by Year 3, because ongoing cost becomes hardware refresh plus a support tier rather than a per-CPU subscription. VCF pricing is quote-driven and non-public, so the real answer depends on your renewal quote and hardware age and is computed during assessment.

Can Cozystack run both virtual machines and containers?

Yes. Cozystack uses KubeVirt so VMs and containers coexist on one Kubernetes API. This contrasts with VMware, where Tanzu is an OpenShift-style container add-on layered onto a VM-first platform.

When is VMware still the better choice?

When the gaps matter more than the licence. VMware has two decades of operational depth (DRS, Storage DRS, Fault Tolerance, vVols), a certified hardware compatibility list a vendor will support you on, and a backup and DR ecosystem — Veeam, Commvault, Rubrik, Zerto, Site Recovery Manager — that speaks VADP natively. Some application vendors certify only against ESXi. If your team is deep on vSphere, renewal economics are tolerable, and nothing else is pushing, stay and tune.

Does Aenix need access to our environment to support Cozystack?

No. Aenix works through an advisory and GitOps PR-review model: we review manifests and runbooks in your repository and never need direct kubectl access to your cluster. Cozystack runs on your hardware with customer-controlled keys.

Planning your migration?

Start with a fixed-price Platform Readiness Assessment — architecture review, gap analysis, and a roadmap you can take to the board.