[CKNE Exam Prep] 1.1 — Installing and Configuring CNI Plugins

Kyle Law

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Sep 22, 2026

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Kubernetes relies on CNI for the underlying Networking.

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Kubernetes without CNI

• the nodes would be ‘Not Ready’ status
• Some pods would be Running, some Pending
• The pods running, they’re running on ‘hostNetwork’, meaning they’re running on the Node IP itself, not on Cluster Pod Network.

Try it yourself — Install CNI

1. Setup Kubernetes with kubeadm init
2. Before installing CNI, check

• kubectl get node
• kubectl get po -owide -A
• kubectl run po --image=nginx
• sudo ls /etc/cni/net.d
• sudo ls /opt/cni/bin

3. For observation, create a file sudo touch /etc/cni/net.d/test.conflist

4. Install Cilium CNI (the de facto CNI for CKNE exam), observe the above commands again

What’re the differences? Share in the comment below :)

Note: You could also observe ‘pre-CNI state’ by going to killercoda playgrounds > Kubernetes playground, then run cilium uninstall and sudo rm /etc/cni/net.d/, the nodes would be ‘Not Ready’ afterwards.