Azure CNI Overlay: Scalable Pod Networking

Traditional vs Overlay Networking

Traditional Azure CNI assigns VNet IPs to pods, limiting scale. Overlay mode uses a separate address space for pods.

Enabling Overlay Mode

az aks create \
    --resource-group myResourceGroup \
    --name myAKSCluster \
    --network-plugin azure \
    --network-plugin-mode overlay \
    --pod-cidr 192.168.0.0/16

Configuration

# Node configuration
nodeConfig:
  networkPlugin: azure
  networkPluginMode: overlay
  podCIDR: 192.168.0.0/16
  serviceCIDR: 10.0.0.0/16

Benefits

• Larger pod address space
• Reduced VNet IP consumption
• Better scalability
• Maintained Azure integration

Migration Considerations

# Check current network mode
az aks show --resource-group myRG --name myAKS --query networkProfile

Summary

Azure CNI Overlay solves IP exhaustion challenges while maintaining Azure network integration, enabling larger AKS deployments.