Kubernetes Network Policies Onboarding Guide

The first packet hits the cluster. You need control, or the network turns into noise. Kubernetes Network Policies give you that control. They define which pods can talk to each other, and to the world beyond. Without them, your workloads are exposed.

This onboarding process is direct and repeatable. Start with a clear map of your namespaces and the traffic they need. In Kubernetes, every connection is pod-to-pod or pod-to-service. Network Policies use selectors and rules to allow or block traffic at Layer 3 and Layer 4. Build the policy designs before you touch YAML.

Step one: enable a CNI plugin that supports Network Policies. Calico, Cilium, and Kube-router are common choices. Without a supported CNI, Network Policies will not enforce anything.

Step two: create a default deny policy for ingress and egress in each namespace. This locks down all traffic until you explicitly open paths. It is the safest baseline for any cluster.

Step three: define allow rules for required flows. Use podSelector and namespaceSelector to target exactly who can connect. Egress rules should reference known external endpoints or CIDRs. Keep the scope tight. A small policy file is easier to audit and maintain.

Step four: test systematically. Apply policies in a staging cluster, run network probes, verify logs from both allowed and denied connections. Adjust rules to remove any unwanted open paths. Automation can help here — integrate policy checks into CI/CD pipelines.

Step five: document everything. Include what each policy does, why it exists, and any dependencies. Good documentation is part of the onboarding. It reduces errors when teams add new services or redeploy workloads.

The Kubernetes Network Policies onboarding process is about control, clarity, and verification. When done right, it closes the gaps attackers look for, while keeping essential traffic flowing.

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