Securing Kubernetes Clusters with Network Policies

What is Zero-Trust Architecture?

In microservice architectures, restricting communication between applications is critical for security. By default, Kubernetes does not block communication between pods. This is where Network Policies come into play.

A Simple Deny-All Rule

The first step is to block all traffic within a namespace by default. The following YAML configuration achieves this:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny-all
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  - Egress

Why is it Important?

• Blocks unauthorized access.
• Prevents lateral movement of malware within the cluster.
• Meets compliance requirements.

Building security layers at every level (Defense in Depth) is a must for modern platforms.