What is KubeVirt?

KubeVirt is an open-source add-on for Kubernetes that lets you run traditional virtual machines (VMs) side-by-side with containers, using the same Kubernetes control plane.

Let's break it down

  • Open-source: Free to use and its code is publicly available for anyone to view or modify.
  • Add-on for Kubernetes: A piece of software you install on top of a Kubernetes cluster to give it extra capabilities.
  • Run traditional virtual machines: Start and manage VMs the same way you would with tools like VMware or KVM.
  • Side-by-side with containers: VMs and containers can live together in the same cluster, sharing networking, storage, and scheduling.
  • Same Kubernetes control plane: You use the familiar Kubernetes API, CLI (kubectl), and dashboards to handle both VMs and containers.

Why does it matter?

It lets organizations reuse their existing VM workloads while they adopt containers, avoiding a costly “lift-and-shift” rewrite. By managing VMs through Kubernetes, teams get unified tooling, better resource utilization, and smoother migration paths to cloud-native architectures.

Where is it used?

  • Legacy application migration: Companies keep old monolithic apps in VMs but schedule them alongside new microservices in the same cluster.
  • Edge and IoT deployments: Devices that need full OS isolation run VMs on edge-Kubernetes clusters, while lightweight services run as containers.
  • Testing and CI/CD pipelines: Test suites spin up VMs for integration tests within a Kubernetes job, then tear them down automatically.
  • Multi-tenant SaaS platforms: Providers give each customer an isolated VM for custom software while delivering shared services as containers.

Good things about it

  • Unified management: One API and CLI for both VMs and containers.
  • Better resource packing: Scheduler can place VMs where capacity exists, improving utilization.
  • Consistent security policies: Same network and RBAC rules apply to VMs and containers.
  • Portability: Works on any Kubernetes-compatible infrastructure (on-prem, public cloud, edge).
  • Community-driven: Backed by Red Hat and the CNCF ecosystem, with regular updates.

Not-so-good things

  • Performance overhead: Running a VM inside Kubernetes adds a layer of abstraction, which can be slower than bare-metal VMs.
  • Complexity for beginners: Requires knowledge of both Kubernetes and virtualization concepts.
  • Limited feature parity: Advanced VM features (e.g., live migration, GPU passthrough) may not be as mature as in dedicated hypervisors.
  • Storage integration challenges: Not all storage classes support the block-level needs of VMs out of the box.