Supported CNI and CRI¶

This document outlines the supported Container Network Interface (CNI) plugins and Container Runtime Interface (CRI) implementations with the Karpenter IBM Cloud Provider.

Container Network Interface (CNI) Support¶

Tested and Supported CNI Plugins¶

CNI Auto-Detection¶

The Karpenter IBM Cloud Provider includes automatic CNI detection in cloud-init bootstrap mode:

apiVersion: karpenter.ibm.sh/v1alpha1
kind: IBMNodeClass
spec:
  bootstrapMode: cloud-init  # Enables auto-detection
  # CNI will be automatically detected and configured

Detection Process: 1. Scans cluster for CNI-specific DaemonSets and ConfigMaps 2. Identifies CNI plugin from kube-system namespace resources 3. Configures node networking accordingly 4. Falls back to generic CNI configuration if detection fails

CNI-Specific Configuration¶

Calico Configuration¶

• Detection: Looks for calico-node DaemonSet
• Configuration: Automatically configures IPPool and network policies
• Features: Full support for network policies and BGP routing

Cilium Configuration¶

• Detection: Looks for cilium DaemonSet and ConfigMap
• Configuration: Configures eBPF datapath and cluster mesh
• Features: Advanced security policies and observability

Flannel Configuration¶

• Detection: Looks for kube-flannel DaemonSet
• Configuration: Sets up VXLAN overlay networking
• Features: Basic pod-to-pod communication

Container Runtime Interface (CRI) Support¶

Supported Container Runtimes¶

Runtime Auto-Detection¶

Automatic Detection Process: 1. Queries existing cluster nodes for runtime information 2. Reads node.status.nodeInfo.containerRuntimeVersion 3. Configures new nodes with the detected runtime 4. Falls back to containerd if detection fails

Manual Runtime Configuration:

# Set via environment variable
export CONTAINER_RUNTIME=containerd

# Or configure in bootstrap script
echo "CONTAINER_RUNTIME=containerd" >> /etc/environment

Custom Configuration¶

Advanced CNI Configuration¶

apiVersion: karpenter.ibm.sh/v1alpha1
kind: IBMNodeClass
spec:
  bootstrapMode: cloud-init
  userData: |
    #!/bin/bash
    # Custom CNI configuration
    curl -L -o /opt/cni/bin/my-cni https://releases.example.com/cni
    chmod +x /opt/cni/bin/my-cni

    # Custom CNI config
    cat > /etc/cni/net.d/10-mycni.conf <<EOF
    {
      "cniVersion": "0.4.0",
      "name": "mycni",
      "type": "my-cni"
    }
    EOF

Runtime Configuration Override¶

spec:
  userData: |
    #!/bin/bash
    # Force specific container runtime
    export CONTAINER_RUNTIME=cri-o

    # Install CRI-O
    curl -L -o /tmp/crio.tar.gz https://releases.cri-o.io/...
    tar -xzf /tmp/crio.tar.gz -C /
    systemctl enable --now crio