Networking in Kubernetes

Networking is a central part of Kubernetes, but it can be challenging to understand exactly how it is expected to work. There are 4 distinct networking problems to address:

1. Highly-coupled container-to-container communications
2. Pod-to-Pod communications
3. Pod-to-Service communications
4. External-to-Service communications

Table of Contents

• Networking in Kubernetes
  • Table of Contents
  • Why is Networking Important in Kubernetes?
  • Creating Network Policies
  • Using Network Policies
  • Networking Limitations
  • Cheat Sheets

Why is Networking Important in Kubernetes?

Networking in Kubernetes provides the communication path between different components. It ensures that these components can communicate with each other and with other applications or systems.

Creating Network Policies

You can create Network Policies using the kubectl apply -f with a Network Policy YAML, or via the Kubernetes API.

Using Network Policies

Network Policies specify how groups of pods are allowed to communicate with each other and other network endpoints.

Networking Limitations

Network Policies are implemented by the network plugin, so you must be using a networking solution which supports NetworkPolicy.

Cheat Sheets

Name	Command
Create a Network Policy	kubectl apply -f networkpolicy.yaml
Get Network Policies	kubectl get networkpolicies
Describe a Network Policy	kubectl describe networkpolicy <NAME>
Delete a Network Policy	kubectl delete networkpolicy <NAME>
Get a Network Policy’s podSelector field	kubectl get networkpolicy <NAME> -o jsonpath='{.spec.podSelector}'
Get a Network Policy’s specific podSelector field	kubectl get networkpolicy <NAME> -o jsonpath='{.spec.podSelector.<KEY>}'
Patch a Network Policy	kubectl patch networkpolicy <NAME> -p '{"spec":{"podSelector":{"key":"new value"}}}'
Replace a Network Policy	kubectl replace -f networkpolicy.yaml