Overlay networking

By default, CDW uses CNI overlay networking.

Default CDW networking

Using Azure Container Networking Interface (CNI), every pod gets an IP address from the node subnet and is accessed directly. Each IP address must be unique across your network space, and you must plan for them in advance of deploying your CDW cluster. Each node has a configuration parameter for the maximum number of pods that it can support. The equivalent number of IP addresses per executor node is reserved up front for it. This requires advanced planning and it can often lead to IP address exhaustion. As an alternative, you must rebuild the cluster in large subnets so your cluster can meet your applications' demands. You can configure the maximum pods that are deployable to an executor node when you create the cluster or when you create new executor node pools. However, if you do not specify the maximum number of pods for the maxPods property when you create new executor node pools, by default each executor node gets 30 pods (with one IP address per pod).

About using overlay networking

To avoid IP address exhaustion, you can enable the overlay networking feature when you activate an Azure environment to use with CDW. For a full description of CNI Overlay networking in AKS, see the Microsoft documentation.