In a cloud-native era where Kubernetes dominates orchestration, one challenge consistently remains: how do you manage legacy virtual machines (VMs) while continuing to adopt containers and microservices? This friction between traditional and modern workloads can create silos in infrastructure, separate CI/CD workflows, and increased complexity in monitoring and operations.
Enter KubeVirt, a Kubernetes extension designed specifically to integrate virtual machines (VMs) into the Kubernetes ecosystem. With KubeVirt, organizations no longer have to choose between VMs and containers. Instead, they gain the ability to run both side by side on the same Kubernetes cluster, using the same Kubernetes primitives, tooling, policies, and management approaches.
This blog is a deep-dive guide for developers, DevOps engineers, and platform teams, exploring how KubeVirt runs VMs like containers, enabling hybrid workloads, increasing efficiency, simplifying operations, and unlocking modernization strategies without painful migrations. It is tailored for hands-on professionals looking to implement real solutions in the real world.
Containers have taken over the development and deployment landscape because of their portability, speed, and scalability. They’re lightweight, easy to distribute, and make microservice-based architectures extremely agile. However, many enterprises still rely heavily on legacy applications that are packaged as virtual machines due to operating system dependencies, monolithic architecture, or lack of container compatibility.
Virtual machines provide full OS-level abstraction. They are widely used in organizations to run mission-critical applications that depend on specific OS versions, Windows environments, or highly regulated and certified setups that cannot be easily re-platformed. Many of these workloads are not easily containerized, if at all.
Running VMs and containers in two separate infrastructures typically means:
This separation creates inefficiencies, slows innovation, and introduces operational debt. That’s where KubeVirt shines.
KubeVirt is an open-source virtualization add-on for Kubernetes that allows developers and operations teams to run virtual machines as Kubernetes resources. Instead of replacing Kubernetes or traditional virtualization platforms like VMware, KubeVirt extends Kubernetes to support VMs in the same way it manages container workloads.
KubeVirt gives your virtual machines native Kubernetes treatment, complete with scheduling, health checks, networking, storage, and declarative configurations.
Because developers can define and manage VMs using YAML, just like they do with Pods or Deployments. Because CI/CD workflows can spin up test environments in either format. Because infrastructure teams can monitor all workloads with the same Prometheus + Grafana stack. This convergence creates operational simplicity with immense strategic benefits.
KubeVirt introduces a few Custom Resource Definitions (CRDs) into the Kubernetes API:
These resources enable VMs to be treated just like Pods: schedulable, scalable, and restartable based on cluster conditions.
KubeVirt introduces multiple controller components that manage virtualization inside Kubernetes:
KubeVirt uses KVM (Kernel-based Virtual Machine) and QEMU (Quick Emulator) under the hood for hypervisor functionality. Because most modern CPUs support virtualization natively (Intel VT-x/AMD-V), performance is near-native.
All standard Kubernetes features can be applied to virtual machines:
With KubeVirt, there’s no need to maintain a separate OpenStack, vSphere, or other virtualization platform alongside Kubernetes. Everything is unified under one control plane, making infrastructure simpler and less costly.
Developers and SREs can now:
By defining VMs declaratively in YAML, they become part of your version-controlled codebase. CI/CD tools like ArgoCD, Flux, Jenkins, or GitHub Actions can be used to:
This was previously impossible without custom scripts and manual VM provisioning systems.
RBAC, network policies, and audit logs can now include VM workloads. You can restrict who creates or modifies VM definitions, control their network access, and log changes centrally.
VMs can be migrated from one node to another without any downtime, allowing infrastructure upgrades, scaling, or hardware failures to occur without affecting application availability.
Virtual Machines can be paused during idle periods to save compute costs and resumed instantly when needed. This dynamic lifecycle is crucial for test/dev or event-driven workloads.
With PCI passthrough and SR-IOV, KubeVirt supports hardware-accelerated applications, enabling powerful AI/ML, media processing, or telco edge workloads.
KubeVirt integrates seamlessly with Kubernetes networking, but also supports multi-networking, VLAN, bridge, and SR-IOV for performance-intensive applications.
Attach block, file, or cloud-native storage to VMs via Persistent Volumes. VMs can use the same CSI plugins as containers do, enabling consistent backups, snapshots, and data mobility.
Run monolithic or uncontainerizable applications in VMs, surrounded by a mesh of microservices, all orchestrated by Kubernetes.
Use KubeVirt to spin up full-blown Ubuntu, CentOS, or Windows test environments, enabling regression tests, driver testing, or compatibility validation with real OS kernels.
Deploy latency-sensitive workloads on edge nodes using SR-IOV and real-time VMs with KubeVirt. Handle millions of packets per second with custom VMs sitting right next to sidecar containers.
Leverage Kubernetes native tools like Velero and volume snapshots to back up both container and VM workloads uniformly.
Traditional hypervisors like VMware ESXi or Hyper-V require their own:
And are not designed for cloud-native workflows.
Use kubectl apply or Helm to deploy the virt-operator and CRDs.
Create a YAML like this (simplified):
apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
name: ubuntu-vm
spec:
running: true
template:
spec:
domain:
devices:
disks:
- disk:
bus: virtio
name: rootdisk
resources:
requests:
memory: 2Gi
volumes:
- name: rootdisk
containerDisk:
image: kubevirt/cirros-container-disk-demo
kubectl apply -f ubuntu-vm.yaml
kubectl get vmis
Add to Git repo, trigger deploys via webhook or pull requests. Deploy alongside container services, perfect for hybrid cloud-native delivery.
KubeVirt is not a replacement for containers, it’s an enabler for legacy and hybrid applications to live in the same Kubernetes-native world. For developers, DevOps teams, and SREs, it unlocks:
As the lines between virtual machines and containers blur, KubeVirt is the bridge to a truly unified platform, accelerating modernization, reducing operational overhead, and giving developers the power to build, test, and run applications without compromise.