Migrating VMs with Shared Virtual Disks using OpenShift Migration Toolkit

This page describes the high-level migration workflow for virtual machines with shared disks using OpenShift Migration Toolkit for virtualization.

1. Migrate First VM with Shared Disks.

   # Plan for first VM — set migrateSharedDisks: true
   apiVersion: forklift.konveyor.io/v1beta1
   kind: Plan
   metadata:
   name: rdm-stage1-plan
   spec:

   migrateSharedDisks: true # <-- required for stage 1 only

   pvcNameTemplateUseGenerateName: true
   targetNamespace: ${FORKLIFT_NAMESPACE}
   warm: false

   ... provider, map, etc. as per standard workflow

   vms:
   - id: vm-cluster-node-01 # First VM only
   name: cluster-node-01

2. Migrate Remaining VMs.

   # Second plan — migrateSharedDisks must be false
   # Otherwise Forklift migrates one copy of RDMs per VM
   apiVersion: forklift.konveyor.io/v1beta1
   kind: Plan
   metadata:
   name: rdm-stage2-plan
   spec:

   migrateSharedDisks: false # <-- critical: must be false for stage 2

   pvcNameTemplateUseGenerateName: true
   targetNamespace: ${FORKLIFT_NAMESPACE}
   warm: false
   vms:
   - id: vm-cluster-node-02
   name: cluster-node-02
   - id: vm-cluster-node-03
   name: cluster-node-03
   - id: vm-cluster-node-04
   name: cluster-node-04
   - id: vm-cluster-node-05
   name: cluster-node-05
   - id: vm-cluster-node-06
   name: cluster-node-06
   Post-Migration: Reconnect VMs to Shared Volumes

3. After the above 2 steps complete, reconfigure the shared RDM volumes as LUN-type SCSI disks on all cluster VMs. The first migrated VM retains ownership of the shared disk PVCs. Configure the remaining VMs to attach those existing PVCs as shared LUNs.
   1. In the OpenShift web console, navigate to the first migrated VM and go to Storage.
   2. For each shared disk, edit the disk, change Drive Type from 'Disk' to 'LUN', change Interface from 'virtio' to 'SCSI'.
   3. For each additional VM, navigate to Storage > Add Disk, select the shared disk, set Type to 'LUN' and Interface to 'SCSI'.
   4. Repeat for all shared disks and all remaining VMs.