Two ways to sell cloud from your own racks. One is a licensed hyperconverged stack with OpenStack underneath; the other is open source on Kubernetes with a managed-services catalogue on top.
Pairs with: Ænix Public Cloud Platform — Cozystack with the commercial surfaces a hosting business needs: billing, the WHMCS integration, a branded customer portal, tenant lock and suspension. Moving an existing estate? The Virtuozzo migration hub covers the three Virtuozzo products path by path.
Who this comparison is for
Virtuozzo is sold largely through hosting providers and service providers, who rebrand it and resell VMs, storage and containers to their own customers. That is the same audience Cozystack’s public-cloud use is built for, so the question here is narrow: if you run, or are about to buy, Virtuozzo Infrastructure (formerly Virtuozzo Hybrid Infrastructure) to sell IaaS, what changes on Cozystack?
Virtuozzo renamed its products in 2026. The IaaS is now Virtuozzo Infrastructure, the PaaS formerly called Application Platform (originally Jelastic) is Virtuozzo Application Management, and the container-and-VM host formerly called Hybrid Server is Virtuozzo Server. This page compares against Virtuozzo Infrastructure, the product a hosting provider replaces with Cozystack. Virtuozzo Server and Application Management are not like-for-like comparisons; the migration hub explains what happens to them.
At a glance
| Virtuozzo Infrastructure | Cozystack | |
|---|---|---|
| Licence | Commercial licence keys (lease, annual, perpetual) counting physical CPU cores and used logical storage | Apache 2.0, no licence fee |
| Orchestration | OpenStack (Nova, Neutron, Cinder, Glance, Keystone, Octavia, Magnum) | Kubernetes; VMs via KubeVirt |
| Hypervisor | KVM | KVM through KubeVirt |
| Storage | Virtuozzo Storage: file, block (iSCSI) and S3 in one software-defined layer | LINSTOR/DRBD replicated block storage; S3 via SeaweedFS |
| Multi-tenancy | Domains, projects and users; self-service panel | Nested Tenant objects with quotas, network isolation and per-tenant observability |
| Kubernetes for customers | Kubernetes as a Service | Managed Kubernetes clusters per tenant |
| Managed databases and brokers | Not part of the IaaS product | PostgreSQL, MariaDB, Valkey, ClickHouse, Kafka, RabbitMQ, NATS, MongoDB, OpenSearch, Qdrant |
| Load balancing | Load Balancer as a Service | Services of type LoadBalancer, Cilium with BGP or L2 announcements |
| Backup | Backup Gateway for Acronis Cyber Protect; Backup and Restore as a Service | Velero with encrypted backups to S3-compatible storage |
| VM high availability | Automatic evacuation of VMs from a failed node, on by default | Live migration for planned maintenance; after unplanned node loss, VMs restart only once the node is fenced |
| GPU | GPU passthrough and vGPU for VMs | VMs: PCI passthrough or NVIDIA vGPU (your NVIDIA licence). Tenant Kubernetes: MIG partitions via the GPU Operator, HAMi time-slicing |
| Billing | CloudBlue connector documented by Virtuozzo; third-party WHMCS modules | Ænix Billing and WHMCS integration (proprietary Ænix modules, in every Public Cloud Platform tier) |
Architecture: OpenStack underneath versus Kubernetes underneath
Virtuozzo describes Infrastructure as a hyperconverged solution providing storage, compute and network resources for businesses and service providers. Underneath the vendor’s management layer it is OpenStack: administrators reconfigure Nova, Cinder and Neutron through Kolla-Ansible, and the documentation drives it with the standard openstack client against Keystone.
That has two consequences for a provider. The first is good: the APIs are familiar, tooling written for OpenStack works, and Virtuozzo has packaged an otherwise demanding stack into something a smaller team can install and run. The second is that the product shape is OpenStack’s — compute, block, networks, images — with Kubernetes offered as one more service on top.
Cozystack inverts that. Kubernetes is the control plane for everything, virtual machines run as KubeVirt workloads next to containers, and every service a tenant can order — a VM, a Kubernetes cluster, a PostgreSQL instance, an S3 bucket — is a declared object reconciled by the platform. Nodes run Talos Linux, an immutable operating system with no SSH. The practical effect is that adding a new managed service is packaging work on one API, not a new OpenStack project to integrate.
Multi-tenancy
Virtuozzo Infrastructure uses the OpenStack model: domains contain projects, domain administrators manage everything in their domain, and project members manage virtual objects in their projects through a self-service panel. It is a well-understood model and maps cleanly to “reseller, then customer”.
Cozystack’s unit is the Tenant. Tenants nest, each carries its own quotas, creating one provisions Cilium network policies that deny traffic from other tenants by default, and each tenant can run its own Kubernetes clusters and managed services with its own monitoring. For a provider whose customers are themselves resellers or agencies, nesting is the feature that matters.
What you can sell: the catalogue
Both platforms sell VMs, Kubernetes and S3. Virtuozzo Infrastructure lists Kubernetes as a Service, Load Balancer as a Service, Backup and Restore as a Service and persistent storage for Kubernetes alongside file, block and S3 object storage.
Where the two diverge is above the infrastructure line. Cozystack ships a catalogue of managed data services that tenants order from the dashboard: PostgreSQL (CloudNativePG), MariaDB, Valkey, ClickHouse, Kafka, RabbitMQ, NATS, MongoDB, OpenSearch and Qdrant, plus S3 (SeaweedFS), HTTP cache and VPN. For a hosting provider that is where margin sits: a managed database is priced per service, not per vCPU, and customers who would otherwise leave for a hyperscaler’s database service can stay.
Storage
Storage is Virtuozzo’s home ground. Virtuozzo Storage is a mature software-defined layer that serves file, iSCSI block and S3 object storage from the same cluster, and Virtuozzo’s Backup Gateway lets Acronis Cyber Protect store backups on it, in public clouds or on NAS.
Cozystack uses LINSTOR with DRBD replication for block volumes, with replication set per StorageClass, and SeaweedFS for S3. Backups go through Velero, encrypted in object storage. It covers the same needs with more components and makes you decide where backups land; it does not offer a single storage product with one vendor behind every protocol.
GPU
Both platforms put GPUs into virtual machines: Virtuozzo documents GPU passthrough and vGPU, and notes that VMs with attached physical GPUs cannot be live-migrated. On Cozystack, VMs get whole GPUs through PCI passthrough or NVIDIA vGPU with your own NVIDIA vGPU licence. Inside tenant Kubernetes clusters, the NVIDIA GPU Operator exposes MIG partitions on MIG-capable cards as schedulable resources, and HAMi adds time-sliced sharing and oversubscription — useful when the product you sell is inference capacity rather than whole cards.
Billing and the commercial layer
A hosting platform is only half a product without billing. Virtuozzo documents a connector that provisions Virtuozzo Infrastructure subscriptions ordered through the CloudBlue commerce platform, with customer projects as the billed assets. WHMCS modules for Virtuozzo products are sold by third parties rather than by Virtuozzo.
On the Cozystack side, the commercial layer comes from Ænix and is proprietary, while the platform stays open source. Ænix Billing reports usage per tenant and per workload — vCPU, memory, volumes by storage class, IP addresses, S3 — at per-minute granularity through a Kubernetes API, and the WHMCS integration turns the catalogue into WHMCS products with provisioning and metering. Both are included in every tier of Ænix Public Cloud Platform, together with a branded customer portal and automatic tenant lock and suspension for overdue accounts.
Licensing and cost
Virtuozzo Infrastructure is licensed with keys that grant a number of physical CPU cores on compute nodes and a logical storage limit, as lease (renewed monthly), annual or perpetual licences; a trial key is limited to 96 cores and 1 TB. Cost therefore grows with cores and stored data.
Cozystack has no licence fee. Ænix sells a subscription — support plus the proprietary commercial modules — priced per 10 physical nodes per month: Basic $1,250, Standard $3,000, Plus $5,500 on annual billing, Enterprise custom (pricing). For a five-year model with sourced Virtuozzo prices at 50, 200 and 1,000 VMs, use the Virtuozzo vs Cozystack TCO calculator; it labels every assumption, including where its Virtuozzo figure is an estimate.
Where Virtuozzo is genuinely better
- VM high availability out of the box. When a compute node fails, Virtuozzo Infrastructure evacuates its running VMs to healthy nodes and starts them, and this is enabled by default when the compute cluster is created. Cozystack has live migration for planned maintenance, but no automatic VM restart after unplanned node loss, because it ships no fencing. Its VMs stay down until the failed node is fenced: an operator marks it out of service or removes it, or an external fencing mechanism does. KubeVirt then restarts them on healthy nodes, and VMs on replicated LINSTOR/DRBD storage come back with their data. Worker nodes of tenant Kubernetes clusters are replaced automatically.
- One storage product for every protocol. File, iSCSI block and S3 from one hyperconverged layer, supported by one vendor, with Acronis backup storage built in. Cozystack assembles the same from LINSTOR, SeaweedFS and Velero.
- No Kubernetes skills required to run it. A team that knows VMs and OpenStack concepts can operate Virtuozzo Infrastructure. Cozystack asks your operators to be comfortable with Kubernetes.
- CloudBlue. If your commerce already runs on CloudBlue, Virtuozzo has a documented connector; Ænix’s modules target WHMCS and your own billing.
If your offer is VMs, S3 and backup, your customers do not ask for managed databases or Kubernetes, and your team is not ready for Kubernetes, staying on Virtuozzo Infrastructure is a reasonable decision.
When Cozystack fits
- You want to sell managed services beyond VMs — databases, message brokers, Kubernetes — without building each one.
- You want to stop paying a per-core licence as the fleet grows.
- Your customers include resellers who need nested tenants.
- You run Virtuozzo Server 7, which passed end of maintenance in July 2024, and need somewhere for those workloads to go — the migration hub covers system containers and KVM guests.
- You are adding GPU capacity and want MIG partitions or HAMi sharing for Kubernetes workloads alongside GPU VMs.
Read more for hosting providers on the industry page.
Sources
Virtuozzo facts on this page come from Virtuozzo’s own documentation, checked in October 2026:
- Virtuozzo Infrastructure 7.4 Administrator’s Guide — Welcome — product description, storage types, Kubernetes, Load Balancer, Backup and Restore as a Service
- Managing licenses (7.4) — licence models and counted resources
- Configuring virtual machine high availability (7.3)
- Configuring GPU passthrough (7.3) and Switching between GPU passthrough and vGPU (5.4)
- Self-Service Guide (7.3) — domains, projects, users
- CloudBlue integration guide
- Virtuozzo product lifecycle policy — Virtuozzo Server 7 end of maintenance
Ænix created Cozystack (CNCF Sandbox project) and co-maintains it with maintainers from other companies. On top of it we offer Ænix Public Cloud Platform, Ænix Private Cloud Platform and Ænix AI Platform.