Understanding Kubernetes: Part 36 Container Network Interface (CNI)

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Container Network Interface (CNI) in Kubernetes

The Container Network Interface (CNI) is a standardized networking framework that allows Kubernetes to manage networking for containers efficiently. CNI is crucial for pod-to-pod communication, service discovery, and traffic routing within a Kubernetes cluster.

Before CNI, networking in Kubernetes was tightly coupled with the container runtime. CNI decouples the networking layer, making it easier to integrate different networking solutions without modifying Kubernetes core components.

Why is CNI Important?

1. Standardization — Provides a uniform way to configure networking across different container runtimes.
2. Extensibility — Enables Kubernetes to use various network plugins like Calico, Flannel, Cilium, Weave, etc.
3. Dynamic Configuration — Automatically assigns IPs and manages routing as pods scale up and down.
4. Isolation & Security — Supports network…