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Module 4 — OpenShift Virtualization

Audience: Platform engineers who need to run and migrate VMs on Kubernetes/OpenShift.

Outcomes: Create, start, stop, and migrate VMs; connect storage/networking; understand KubeVirt primitives (VirtualMachine, VirtualMachineInstance, DataVolume) as Kubernetes resources — because that is what they are; perform live migration and plan bulk migration from vSphere (MTV).

Prerequisite: Module 3 substantially complete. A VirtualMachineInstance is a Pod — you cannot operate it without understanding Pods, scheduling, networking, and storage.

Checklist — work through in order

  • Confirm Module 3 is substantially complete (a VMI is a Pod)
  • Read the mental model + skim About OpenShift Virtualization
  • Browse the Red Hat OpenShift Virtualization learning hub and kubevirt.io for the upstream project
  • Create/start/stop a VM; find its backing VMI Pod
  • Practice live migration (needs multi-node + RWX) and walk one MTV migration plan
  • Formal course: DO317 — Managing VMs with OpenShift Virtualization (includes EX316 exam)
  • Pass the scenario-based Verification at the bottom

Mental model

OpenShift Virtualization runs VMs inside Kubernetes via KubeVirt. The hypervisor is a process inside a Pod. The scheduler does not know or care it’s a VM. This is why Modules 2–3 come first.

Topics

  • KubeVirt primitives — VirtualMachine (desired-state), VirtualMachineInstance (running Pod with hypervisor), DataVolume (managed PVC + import pipeline)
  • VM networking — secondary networks via NAD; pod overlay (OVN) vs bridge-attached VLANs
  • VM storage — DataVolume import (HTTP/registry/PVC clone); RWX requirement for live migration; VolumeSnapshot for disk backups
  • Live migration — mechanism, objects (VirtualMachineInstanceMigration), shared-storage + node-scheduling requirements
  • Migration Toolkit for Virtualization (MTV) — bulk vSphere import: source inventory, network maps, storage maps, cutover
  • Performance tuning (read-ahead) — CPU pinning/NUMA (dedicatedCpuPlacement), HugePages, SR-IOV, real-time kernel, Node Tuning Operator

Official

Formal courses: DO317 — Managing VMs with OpenShift Virtualization (includes EX316 exam); DO156 Administration I as an alternative entry point.

Verification (scenario-based)

  1. Create a VM from template/YAML; console/SSH in; find the backing VMI Pod via oc get pods; describe it; confirm it’s what Kubernetes schedules.
  2. Live migration (multi-node + RWX required; not on SNO): migrate between workers; explain which K8s mechanisms determined placement. SNO fallback: trace every object (VirtualMachineInstanceMigration, source/target VMI pods, shared RWX PVC, QEMU channel); explain why SNO can’t (no valid target node) and the minimum topology.
  3. Walk one MTV planning chapter: source inventory, network/storage maps, cutover — even if you migrate only one small VM.