cni-daemonset.yaml

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: demystifying-cni
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: demystifying-cni
  template:
    metadata:
      labels:
        app: demystifying-cni
    spec:
      # running in hostNetwork avoids dependency on CNI (solve chicken-egg problem) 
      hostNetwork: true
      tolerations:
      # ensure to schedule on nodes that are not ready (nodes without a CNI are not ready)
      - key: node.kubernetes.io/not-ready
        operator: Exists
        effect: NoSchedule
      # ensure to schedule on control-plane nodes
      - key: node-role.kubernetes.io/control-plane
        operator: Exists
        effect: NoSchedule
      containers:
      - name: demystifying-cni
        image: demystifying-cni:0.0.1
        volumeMounts:
        - name: netd
          mountPath: /etc/cni/net.d
        - name: cnibin
          mountPath: /opt/cni/bin
      # use hostPath to get access to the node filesystem
      volumes:
      - name: netd
        hostPath:
          path: /etc/cni/net.d
      - name: cnibin
        hostPath:
          path: /opt/cni/bin