Diegolden

Topic 1: Kubernetes Network Model

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Topic 1: Kubernetes Network Model

Official baseline: (The Kubernetes Authors, 2026). My working version: Kubernetes assumes Pods can talk to Pods without NAT. The CNI implementation makes that promise real.

Mental Model

Kubernetes assumes Pods can talk to Pods without NAT. The CNI implementation makes that promise real.

Notes

  • Pod IPs are real within the cluster but not stable application identities.
  • Services provide stable virtual entry points.
  • CNI choice decides dataplane behavior, policy support, and debugging tools.

Homelab Angle

Do not install three CNIs while learning. Pick one and learn how packets move.

Verify It

  • Read the object status before changing the manifest.
  • Check events for the controller or node that is actually complaining.
  • Confirm the official source linked below still matches the cluster version you run.

Common Failure Modes

  • Treating the YAML object as the system, instead of one input to a reconciliation loop.
  • Debugging from outside the cluster when the failure only exists inside cluster networking or node state.
  • Forgetting that Kubernetes version, addon version, and runtime behavior are linked.

Sources

  • Services, Load Balancing, and Networking - source path: content/en/docs/concepts/services-networking/_index.md, commit 8cc9e19b8eec8d5cf49eacd66f86a81648edb1a0.
  • Kubernetes documentation is licensed under CC BY 4.0; these notes are original commentary and link back to the official source.
The Kubernetes Authors. (2026). Services, Load Balancing, and Networking. https://kubernetes.io/docs/concepts/services-networking/

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