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What is the difference between CubeCOS and VMware? CubeCOS is an open-source, self-hosted cloud platform that combines virtualization, Kubernetes, storage, networking, and multi-tenancy into one deployable image. In contrast, VMware is a proprietary, licensed virtualization stack assembled from separate products. CubeCOS replaces VMware's mature ecosystem with open-source control, eliminating vendor lock-in and reducing total cost.
Organizations evaluating a replacement for VMware following Broadcom’s acquisition in 2023 are increasingly comparing CubeCOS and VMware to determine which platform can support enterprise virtualization without introducing operational complexity or unexpected costs.
CubeCOS is an open source enterprise cloud operating system that unifies virtual machine and Kubernetes management on a single platform, positioning itself as a VMware alternative for modern edge, private and public cloud environments.
This article provides an in-depth CubeCOS vs. VMware comparison. The comparison includes virtualization, storage, networking, Kubernetes integration, management experience, scalability, and total cost of ownership. This comparison will help you determine which platform best fits your infrastructure requirements.
CubeCOS vs. VMware at a Glance
| Capability | VMware | CubeCOS |
|---|---|---|
| Hypervisor/Compute | Proprietary ESXi (type-1, baremetal). Live migration via vMotion; workload balancing via DRS. | Open-source KVM (type-1, baremetal). Live migration and workload placement handled natively through OpenStack Nova. Same core performance, no stack lock-in. |
| Networking | NSX core license. Overlay SDN and distributed micro-segmentation. Load balancing, advanced firewall, and other features required additional NSX licensing. | Integrated SDN built-inOpenStack Neutron (OVN/ OVS overlay). Distributed security groups, micro-segmentation, and build-in load balancer (ASG support included). |
| Storage | vSAN. Hyperconverged storage requires vSAN Ready node certified hardware (HCL-locked) with capacity-based pricing. | Ceph. Distributed block, object, and file storage. Reliable, horizontally scalable, and runs on standard commodity x86 servers without capacity constraints. |
| Containers | VKS. Includes Kubernetes runtime in VCF. Full Tanzu features and licensing are sold separately. | Native Kubernetes. Built into the platform with multi-cluster, version and tenant integration. No additional framework or management interface is required. |
| Source model | Closed source. Roadmap, fixes, and feature timing are entirely controlled by Broadcom/VMware. | Open source (Apache 2.0). Inspectable codebase, community contribution, no single-vendor roadmap dependency. |
| Hardware compatibility | Restricted to the VMware Hardware Compatibility List (HCL) — limits vendor choice and can force early refresh cycles. | Vendor-agnostic. Runs on commodity x86 hardware from any vendor, extending the useful life of existing infrastructure. |
| Licensing model | Per-core VCF subscription. Costs are directly proportional to the number of cores, regardless of actual utilization. | No platform licensing fee. Enterprise support is available as an optional subscription, with the cost decoupled from the number of cores. |
| Automation tooling | VCF Automation (formerly Aria/vRealize). Proprietary, VMware-specific workflows and APIs. | Open APIs. Integration with common tools in existing DevOps pipelines: Terraform, Ansible, and Helm. |
| Air-gapped deployment | Supported. It is still subject to periodic license validation. This is a constraint in fully isolated or sovereign environments. | Native support. No license-validation requirement at all. Suited to regulated, sovereign, or disconnected deployments. |
| Vendor lock-in | High. Proprietary APIs and tightly coupled components make migrating off the stack costly and slow. | Low. Open standards and modular components mean no single point of dependency. |
Why VMware Alternatives Are Imperative in 2026
The Broadcom transition introduced structural changes that extend beyond pricing.
- Bundle-only licensing: VMware Cloud Foundation (VCF) is now the primary commercial offering, requiring customers to purchase compute, storage, and network virtualization as a package, regardless of whether they require all components.
- Per-core pricing: The shift from per-socket to per-core billing significantly increases costs for high-core-count servers, which are common in modern infrastructure.
- Partner ecosystem disruption: Broadcom terminated many of VMware's reseller and support partner agreements, which complicates procurement and support for enterprise customers.
For organizations that have built their infrastructure around VMware, this isn't just another vendor change. It's a catalyst for architectural review.
Discover the Top VMware Alternatives in 2026.
Platform Overview
VMware ESXi/VCF is a mature, proprietary, hypervisor-based platform with over two decades of enterprise adoption. Its core components, ESXi (hypervisor), vCenter (management), vSAN (distributed storage) and NSX (software-defined networking), are deeply integrated but separately licensed. Under Broadcom, VCF bundles these into a single subscription model.
CubeCOS is an open-source cloud operating system designed for enterprises running hybrid and on-premises infrastructure. It provides unified management of KVM-based virtual machines and Kubernetes workloads from a single control plane, with built-in distributed storage, software-defined networking and multi-tenancy.
Technical Deep Dive
Hypervisor and Compute Virtualization
VMware ESXi is a type 1 bare-metal hypervisor with a long track record of stability and hardware compatibility. It remains one of the most battle-tested hypervisors available and is deeply integrated into server vendor certification programmes (Dell, HPE and Lenovo).
CubeCOS runs on KVM (Kernel-based Virtual Machine) combined with QEMU for device emulation and libvirt for lifecycle management, KVM provides enterprise-grade compute virtualization without any proprietary dependencies.
CubeCOS supports PCIe passthrough for GPU, UEFI/Secure Boot, vTPM 2.0 and full Windows Server support covering the majority of VMware workload types without modification.
Storage Architecture
VMware vSAN provides hyperconverged storage by pooling local NVMe/SSD/HDD drives across ESXi hosts into a distributed datastore. It is tightly integrated with ESXi, but vSAN capacity licensing is required (this is included in VCF). Policy-based storage management (SPBM) enables per-VM storage quality of service (QoS), granular data protection configuration without the need for external storage.
CubeCOS uses Ceph as its distributed storage backend. Ceph supports tiered storage pools, erasure coding and replication policies that can be configured on a per-pool basis, which covers the core use cases addressed by SPBM.
- Ceph RBD (RADOS Block Device): Provides block storage for virtual machines (VMs).
- CephFS: Provides shared file system access.
- RADOS Gateway: S3-compatible object storage.
CubeCOS also integrates external storage via iSCSI, Fibre Channel and NFS, providing enterprises with existing SAN investments with a direct integration path rather than requiring them to replace their systems.
Networking
VMware's NSX is a software-defined networking layer that provides distributed firewall, micro-segmentation and GENEVE-based overlay networking. While it is powerful and feature-rich, it is also one of the most expensive components in the VCF stack, requiring dedicated expertise to operate.
CubeCOS uses OVN (Open Virtual Network) and Open vSwitch for software-defined networking. OVN provides CubeCOS with distributed L2/L3 networking, network ACLs, NAT, load balancing, and GENEVE-based overlay networking. Micro-segmentation at the tenant and project level is enforced through network policies tied to CubeCOS's multi-tenancy model.
For teams transitioning from NSX, CubeCOS's software defined network offers functional parity for core use cases, eliminating the need for proprietary lock-in.
Upgrade and Lifecycle Management
ESXi upgrades are managed through vCenter Update Manager (vLCM) and require careful sequencing across ESXi hosts, with rolling reboots that depend on DRS and HA settings. In large clusters, upgrades can be operationally intensive, particularly when hardware vendor firmware updates are involved.
CubeCOS performs rolling upgrades across the cluster. It has automated virtual machine (VM) evacuation and partition swap logic, as well as a safe rollback process in case of failure. Upgrades proceed node by node, maintaining workload availability throughout the process and eliminating the need for a separate lifecycle management tool. Cluster operations continue uninterrupted, even during management node upgrades.
When to Choose VMware
VMware ESXi / VCF remains the right call in a narrow set of cases:
- You have existing multi-year VCF contract with favourable renewal terms.
- Your workload relies heavily on VMware-specific integrations, such as ESXi-native backup solutions and ESXi-integrated third-party security tools, for which there is not yet a mature open-source equivalent.
- Your operations team has significant, in-depth VMware expertise, and retraining is not currently feasible.
The correct evaluation is workload-specific, not categorical.
When to Choose CubeCOS
CubeCOS is the stronger choice when:
- You're standing up a greenfield deployment and want to start on open-source infrastructure instead of inheriting vendor lock-in from day one.
- You can shift your workloads to a cloud-native tools and an open source ecosystem. This means trading per-core licensing and a single vendor's roadmap for Apache 2.0 licensing and the freedom to swap components as your needs change.
- As a cloud or service provider, you need full technical, data, and operational ownership of your infrastructure, not just a tenant's view of someone else's stack.
CubeCOS Migration Considerations
A direct VMware-to-CubeCOS migration typically involves three phases:
- Assessment: Inventory existing VMware workloads by VM type, OS, storage backend and network policy. Identify workloads that are suitable for a 'lift-and-shift' approach versus those that require re-platforming.
- Pilot deployment: Set up a CubeCOS cluster in parallel, migrate a subset of critical VMs using disk image export/import, and validate storage and network parity.
- Phased cutover: Migrate workloads by priority tier with rollback checkpoints. Decommission VMware hosts as each batch is validated.
Thanks to CubeCOS's OpenStack-compatible API, organizations that use automation tools targeting OpenStack, such as Terraform, Ansible, and the Python SDK, can reuse most of their existing tools.
Start Your VMware Migration to CubeCOS
Bigstack CubeCOS is designed for organizations that need a modern, open, and AI-ready alternative to VMware, offering a solution without vendor lock-in or unpredictable licensing costs.
Whether you're running traditional virtual machine (VM) workloads, GPU-intensive artificial intelligence (AI) infrastructure, or a mix of both, CubeCOS provides a unified platform to consolidate your infrastructure and simplify day-two operations.
See how CubeCOS migrates VMware workload seamlessly → Migration tool
Here's how to take the next step:
Audit your current environment
Take stock of your existing VMware components, workloads and dependencies to determine your requirements for a VMware replacement platform.
What to capture in your audit
- Active VMs and their resource profiles (CPU, RAM, storage)
- Licensing costs across vSphere, vCenter, NSX, and add-ons
- Dependencies between workloads that affect migration sequencing
- Any GPU or AI workloads that require specialized infrastructure support
See CubeCOS in action
Request a CubeCOS demo tailored to your current VMware feature set. Rather than a generic walkthrough, Bigstack maps CubeCOS capabilities directly to your existing stack so you can see exactly where feature parity exists and where CubeCOS extends beyond what VMware offers.
What the demo covers:
- Side-by-side comparison with your current VMware environment
- Migration pathways specific to your workload profile
- Day-two operations including updates, monitoring, and scaling
Validate with a proof of concept
Talk to a Bigstack infrastructure expert to find out how you can deploy CubeCOS in a controlled test environment alongside your existing stack before making any production commitments.
With a proof of concept, your team can verify performance, compatibility, and operational fit with real workloads rather than synthetic benchmarks.
- Schedule an appointment today → Schedule today
- Simplify day-two operations - Discover how one-click updates and upgrades reduce ongoing maintenance overhead → Learn more
Frequently Asked Questions
What is CubeCOS and how does it compare to VMware?
CubeCOS is an open-source cloud platform that manages both VMs and Kubernetes workloads from a single control plane. VMware (vSphere/VCF) is a proprietary platform that uses ESXi, vSAN and NSX under Broadcom's subscription model.
The core differences:
- CubeCOS is built on open-source components, includes Kubernetes natively, and charges no per-core licensing fees
- VMware bundles everything into VCF and charges per core.
Why should IT teams evaluate VMware alternatives in 2026?
Broadcom's acquisition of VMware in 2023 replaced perpetual licenses with subscription bundles, renewal costs increased three to tenfold, and per-core pricing replaced per-socket billing. For teams running mission-critical workloads on vSphere, vSAN, and NSX, the financial and operational case for evaluating open-source alternatives, such as CubeCOS, has never been stronger.
How does CubeCOS replace VMware without introducing new problems?
CubeCOS is an enterprise-ready cloud infrastructure platform that provides key capabilities such as software-defined networking, distributed storage, high availability, workload migration, platform automation, and IT self-service. Additional enterprise modules include CubeVDI for remote office deployments, CubeCMP for hybrid cloud adoption, and CubeDPX for enterprise data protection.
What are the key cost differences between CubeCOS and VMware?
VMware requires a VCF bundle subscription. You pay per core for computing, storage, and networking, regardless of whether you use all components. CubeCOS is open source with no per-core licensing fees and offers enterprise support as an optional add-on. Organizations with high-core-count servers or hybrid virtual machine (VM) and Kubernetes workloads typically reduce costs by 70% after migrating to CubeCOS.
How does CubeCOS handle Kubernetes differently than VMware?
CubeCOS treats virtual machines (VMs) and Kubernetes as equals on one control plane. Teams can provision and manage both types of workloads from the same interface with unified RBAC and project isolation. There is no need for extra licensing or context switching.
What is the migration process from VMware to CubeCOS?
A direct VMware-to-CubeCOS migration typically involves three phases:
- Assessment: Inventory existing VMware workloads by VM type, OS, storage backend and network policy.
- Pilot deployment: Set up a CubeCOS cluster in parallel, migrate a subset of critical VMs using disk image export/import, and validate storage and network parity.
- Phased cutover: Migrate workloads by priority tier with rollback checkpoints. Decommission VMware hosts as each batch is validated.
Which open-source virtualization platforms are viable alternatives to VMware's proprietary solutions?
Several open-source platforms have emerged as credible VMware vSphere/ESXi alternatives, particularly since Broadcom's acquisition prompted many organizations to develop exit strategies. The main options include:
- Bigstack CubeCOS
- KVM (Kernel-based Virtual Machine)
- Proxmox VE
- SUSE Virtualization (formerly Harvester)
- XCP-ng
For a complete side-by-side comparison of costs, storage, networking, high availability (HA), and licensing, our breakdown of VMware alternatives.
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