Network Policies is a new Kubernetes feature to configure how groups of pods are allowed to communicate with each other and other network endpoints. In other words, it creates firewalls between pods running on a Kubernetes cluster. This guide is meant to explain the unwritten parts of Kubernetes Network Policies.
This feature has become stable in Kubernetes 1.7 release. In this guide, I will explain how Network Policies work in theory and in practice. You can directly jump to kubernetes-networkpolicy-tutorial repository for examples of Network Policies or read the documentation.
What can you do with Network Policies
By default, Kubernetes does not restrict traffic between pods running inside the cluster. This means any pod can connect to any other pod as there are no firewalls controlling the intra-cluster traffic.
Read more at Ahmet Alp Balkan