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Configure Azure CNI Powered by Cilium in Azure Kubernetes Service (AKS)

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Azure CNI Powered by Cilium combines the robust control plane of Azure CNI with the data plane of Cilium to provide high-performance networking and security.

By making use of eBPF programs loaded into the Linux kernel and a more efficient API object structure, Azure CNI Powered by Cilium provides the following benefits:

  • Functionality equivalent to existing Azure CNI and Azure CNI Overlay plugins

  • Faster service routing

  • More efficient network policy enforcement

  • Better observability of cluster traffic

  • Support for larger clusters (more nodes, pods, and services)

IP Address Management (IPAM) with Azure CNI Powered by Cilium

Azure CNI Powered by Cilium can be deployed using two different methods for assigning pod IPs:

  • Assign IP addresses from a virtual network (similar to existing Azure CNI with Dynamic Pod IP Assignment)

  • Assign IP addresses from an overlay network (similar to Azure CNI Overlay mode)

If you aren't sure which option to select, read "Choosing a network model to use".

Network Policy Enforcement

Cilium enforces network policies to allow or deny traffic between pods. With Cilium, you don't need to install a separate network policy engine such as Azure Network Policy Manager or Calico.

Limitations

Azure CNI powered by Cilium currently has the following limitations:

  • Available only for Linux and not for Windows.

  • Cilium L7 policy enforcement is disabled.

  • Hubble is disabled.

  • Network policies cannot use ipBlock to allow access to node or pod IPs (Cilium issue #9209 and #12277).

  • Kubernetes services with internalTrafficPolicy=Local aren't supported (Cilium issue #17796).

  • Multiple Kubernetes services can't use the same host port with different protocols (for example, TCP or UDP) (Cilium issue #14287).

  • Network policies may be enforced on reply packets when a pod connects to itself via service cluster IP (Cilium issue #19406).

Prerequisites

  • Azure CLI version 2.48.1 or later. Run az --version to see the currently installed version. If you need to install or upgrade, see Install Azure CLI.

  • If using ARM templates or the REST API, the AKS API version must be 2022-09-02-preview or later.

Note

Previous AKS API versions (2022-09-02preview to 2023-01-02preview) used the field networkProfile.ebpfDataplane=cilium. AKS API versions since 2023-02-02preview use the field networkProfile.networkDataplane=cilium to enable Azure CNI Powered by Cilium.

Create a new AKS Cluster with Azure CNI Powered by Cilium

Option 1: Assign IP addresses from a virtual network

Run the following commands to create a resource group and virtual network with a subnet for nodes and a subnet for pods.

# Create the resource group
az group create --name <resourceGroupName> --location <location>

# Create a virtual network with a subnet for nodes and a subnet for pods
az network vnet create -g <resourceGroupName> --location <location> --name <vnetName> --address-prefixes <address prefix, example: 10.0.0.0/8> -o none 
az network vnet subnet create -g <resourceGroupName> --vnet-name <vnetName> --name nodesubnet --address-prefixes <address prefix, example: 10.240.0.0/16> -o none 
az network vnet subnet create -g <resourceGroupName> --vnet-name <vnetName> --name podsubnet --address-prefixes <address prefix, example: 10.241.0.0/16> -o none

Create the cluster using --network-dataplane cilium:

az aks create -n <clusterName> -g <resourceGroupName> -l <location> \
  --max-pods 250 \
  --network-plugin azure \
  --vnet-subnet-id /subscriptions/<subscriptionId>/resourceGroups/<resourceGroupName>/providers/Microsoft.Network/virtualNetworks/<vnetName>/subnets/nodesubnet \
  --pod-subnet-id /subscriptions/<subscriptionId>/resourceGroups/<resourceGroupName>/providers/Microsoft.Network/virtualNetworks/<vnetName>/subnets/podsubnet \
  --network-dataplane cilium

Note

The --network-dataplane cilium flag replaces the deprecated --enable-ebpf-dataplane flag used in earlier versions of the aks-preview CLI extension.

Option 2: Assign IP addresses from an overlay network

Use the following commands to create a cluster with an overlay network and Cilium. Replace the values for <clusterName>, <resourceGroupName>, and <location>:

az aks create -n <clusterName> -g <resourceGroupName> -l <location> \
  --network-plugin azure \
  --network-plugin-mode overlay \
  --pod-cidr 192.168.0.0/16 \
  --network-dataplane cilium

Upgrade an existing cluster to Azure CNI Powered by Cilium

Note

You can update an existing cluster to Azure CNI Powered by Cilium if the cluster meets the following criteria:

The upgrade process triggers each node pool to be re-imaged simultaneously. Upgrading each node pool separately isn't supported. Any disruptions to cluster networking are similar to a node image upgrade or Kubernetes version upgrade where each node in a node pool is re-imaged.

Cilium will begin enforcing network policies only after all nodes have been re-imaged.

To perform the upgrade, you will need Azure CLI version 2.52.0 or later. Run az --version to see the currently installed version. If you need to install or upgrade, see Install Azure CLI.

Use the following command to upgrade an existing cluster to Azure CNI Powered by Cilium. Replace the values for <clusterName> and <resourceGroupName>:

az aks update -n <clusterName> -g <resourceGroupName> \
  --network-dataplane cilium

Frequently asked questions

  • Can I customize Cilium configuration?

    No, AKS manages the Cilium configuration and it can't be modified. We recommend that customers who require more control use AKS BYO CNI and install Cilium manually.

  • Can I use CiliumNetworkPolicy custom resources instead of Kubernetes NetworkPolicy resources?

    CiliumNetworkPolicy custom resources aren't officially supported. We recommend that customers use Kubernetes NetworkPolicy resources to configure network policies.

  • Does AKS configure CPU or memory limits on the Cilium daemonset?

    No, AKS doesn't configure CPU or memory limits on the Cilium daemonset because Cilium is a critical system component for pod networking and network policy enforcement.

Next steps

Learn more about networking in AKS in the following articles: