Goal

Investigate whether Azure VM-based OCP spoke clusters can meet all CCLM (Cross-Cluster Live Migration) requirements, and deploy a proof-of-concept environment to validate.

Investigation Outcome

Azure IPI VM clusters are confirmed viable for CCLM. Key findings:

• CNV/MTV install successfully on Azure VM workers via the kubevirt-hyperconverged addon
• Custom CIDRs supported at install time – non-overlapping clusterNetwork, serviceNetwork, and machineNetwork can be specified in install-config.yaml
• D8s_v3+ instances required for VM workloads (8 CPU, 32GB RAM minimum for nested virtualization)
• Submariner networking requires additional Azure configuration – public IPs, NSG inbound rules, and either subctl cloud prepare azure or manual portal setup
• Azure BM was ruled out per RFE-4142 – bare metal on Azure is not supported for this use case

What was validated

• Hub + 2 spoke Azure IPI clusters deployed
• CNV operator installed on spokes via addon
• MTV operator installed on hub
• VMs can be created and run on spoke workers

Gaps identified (addressed by subsequent sub-tasks)

• Both spokes had identical CIDRs – Submariner cannot route between them. New clusters needed with unique CIDRs (see ACM-30198).
• Spoke workers were Standard_D2s_v3 (2 CPU, 8GB) – too small for production VMs. Need D8s_v3+ (see ACM-30198).
• No Submariner networking configured – no subctl cloud prepare was run, no manual portal setup (see ACM-30199).
• No RWX storage – Azure managed-csi is RWO only. Azure Files NFS StorageClass needed (see ACM-30200).