实施Kubernetes网络策略：综合指南

Network policies are networking rules in Kubernetes that will allow you to specify how the pod can communicate with other objects.

Network policies are not mandatory to establish communication with pods. However, network policies will add one more layer of network security and help control traffic at Layers 3 and 4 (IP and ports).

The idea of network policy is born in the networking SIG group of Kubernetes in 2015. It was included in the alpha release of v1.2 (2016) and moved to beta in v1.3(July 2016). Below is the proposal for the Network policy by Casey Davenport.