CNI

Check CNI

cat /var/lib/kubelet/config.yaml | grep containerRuntimeEndpoint

CNI supported plugins path

ls /opt/cni/bin

Check configured CNI Plugin

ls /etc/cni/net.d/

# or check the pods

kubectl get pods -A

Install CNI (ex. Calico)

Docs -> Link

1. Install CRDs and Operators

   kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.31.4/manifests/tigera-operator.yaml
   

2. Download Custom Resource manifest

   curl https://raw.githubusercontent.com/projectcalico/calico/v3.31.4/manifests/custom-resources.yaml -O
   

3. Edit custom-resources.yaml and update the cidr

   apiVersion: operator.tigera.io/v1
   kind: Installation
   metadata:
   name: default
   spec:
   # Configures Calico networking.
   calicoNetwork:
       ipPools:
       - name: default-ipv4-ippool
           blockSize: 26
           cidr: x.x.x.x/16  # CHANGE ME
           encapsulation: VXLANCrossSubnet
           natOutgoing: Enabled
           nodeSelector: all()
   

4. Apply manifest

   kubectl apply -f custom-resources.yaml
   

Delete CNI

After removing all k8s resources:

rm /etc/cni/net.d/<cni-conflist>

Check Pod CIDR

kubectl cluster-info dump | grep -m 1 cluster-cidr

# or per-node
kubectl get nodes -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.podCIDR}{"\n"}{end}'

Notes

1. Not all CNI support Network Policies (Flannel does NOT, Calico and Weave do)