VMware to OpenShift Virtualization Series

A 15-part engineering series for teams evaluating, designing and executing a move from VMware vSphere to Red Hat OpenShift Virtualization. Read it in order, or jump to the part you need — every article includes diagrams, commands and acceptance checklists.

Foundations

Conceptual mapping of VMware vSphere concepts to OpenShift Virtualization concepts across execution, management, VM definition, organization, storage, networking, mobility and automationPart 1VMware vs OpenShift Virtualization: Complete Technical ComparisonVMware vSphere vs OpenShift Virtualization compared: architecture, availability, storage, networking, cost and a weighted decision with mandatory gates.8 min readOpenShift Virtualization control path from API to controllers, and data path on the worker node through virt-launcher, QEMU/KVM, guest, storage and networksPart 2OpenShift Virtualization Architecture ExplainedOpenShift Virtualization architecture explained: control path vs data path, virt-controller, virt-handler, virt-launcher, QEMU/KVM and failure domains.8 min readRelationship between VirtualMachine, VirtualMachineInstance, virt-launcher pod, node, DataVolume, PVC and PVPart 3Understanding KubeVirt, VM and VMIKubeVirt VM vs VMI explained: run strategies, launcher pods, DataVolumes and PVCs, lifecycle states and safe power and deletion practices.7 min read

Plan the migration

Five migration phases: discover, qualify destination, choose method, run pilot, build dependency-aware waves, each with its outputPart 4VMware to OpenShift: Complete Migration StrategyA five-phase VMware to OpenShift migration strategy: discovery, method selection, pilots, dependency-aware waves, cutover timing and rollback.8 min readMTV control traffic between the forklift controller, inventory and vCenter is separate from bulk disk traffic between ESXi datastores, transfer and conversion pods and target PVCsPart 5MTV Architecture and Internal WorkingInside the Migration Toolkit for Virtualization: Providers, maps, Plans and Migrations, cold vs warm execution, and diagnosing failures by stage.7 min read

Platform deep dives

A VM with two interfaces: one on the default pod network using masquerade and a Service, one on a secondary Linux bridge connected through a node NIC to a physical VLANPart 6OpenShift Virtualization Networking Deep DiveOpenShift Virtualization networking: pod network vs secondary Linux bridge, packet paths, NNCP and NAD setup, MTU, IP retention and troubleshooting.7 min readDisk ownership chain from VM volume reference to DataVolume, PVC, PV, CSI driver and storage backend, up to the guest-visible disk, with what each object does not provePart 7OpenShift Virtualization Storage Deep DiveOpenShift Virtualization storage explained: DataVolume to PV chain, RWX vs block, capacity planning, performance, snapshots and backups.7 min readThree different migration problems: VMware to OpenShift with MTV, in-cluster VMI live migration between nodes, and cross-cluster live migration which is Technology Preview in 4.20Part 8OpenShift VM Live Migration ExplainedHow OpenShift VM live migration works: pre-copy convergence, eligibility constraints, network and concurrency tuning, post-copy and node drains.6 min readCluster capacity split into five budgets: platform, guest execution, data services, change operations and resilience reservePart 9OpenShift Cluster Sizing for VirtualizationSize an OpenShift Virtualization cluster: five capacity budgets, N+1 memory math, CPU and placement constraints, storage and migration throughput.6 min read

Migrate workloads

Windows VM migration runbook: migration record, Windows baseline, consistency and recovery with VSS, destination mappings, pilot, execute, validate and accept or roll backPart 10Migrating Windows VMs Using MTVA Windows VM migration runbook for MTV: baseline inventory, VSS, mappings, warm cutover, first-boot driver installs and post-conversion checks.6 min readLinux boot chain after conversion: firmware, bootloader, kernel and initramfs with VirtIO drivers, root mount by persistent identifier, systemd mounts, network, application, with what fails at each stagePart 11Migrating Linux VMs Using MTVA Linux VM migration runbook for MTV: guest inventory, VirtIO and initramfs readiness, persistent disk IDs, network profiles and validation.6 min read

Automate and operate

Imperative PowerCLI model where a cmdlet runs a vCenter task, compared with the declarative OpenShift model where oc or virtctl submits desired state that controllers reconcile into observed statePart 12VMware PowerCLI vs OpenShift CLIMap PowerCLI tasks to oc and virtctl, and learn the declarative model: context, JSON objects, requested vs observed state and safe retries.6 min readOcpVirtualization PowerShell module architecture: public Get-OcpVM and Start-OcpVM functions call a private native-command helper that passes an argument array to oc or virtctl, checks the exit code, and returns objectsPart 13Building OpenShift PowerShell CmdletsBuild a safe PowerShell module for OpenShift Virtualization with explicit context, exit-code checks, -WhatIf support and Pester tests.5 min readTroubleshooting layers from API authorization through desired VM state, scheduling, disk population, node execution, guest OS, application and performance, mapped to the seven branches of the guidePart 14OpenShift Virtualization Troubleshooting GuideAn evidence-first troubleshooting guide for OpenShift Virtualization: scheduling, DataVolumes, boot failures, networking, live migration and performance.7 min readEnterprise migration program control flow: discovery, eligibility and grouping, landing-zone qualification, wave plan, MTV execution lanes, acceptance, and protection and retirement, all around a migration system of recordPart 15Enterprise-Scale VMware to OpenShift Migration ArchitectureReference architecture for large VMware-to-OpenShift programmes: landing zones, migration lanes, throughput math, release gates and rollback authority.7 min read
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Engineering notes and guides on VMware vSphere, OpenShift Virtualization, KubeVirt and the Migration Toolkit for Virtualization.

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