Summary

In this chapter, we have learned how containers communicate with each other as it is essential, and we introduced how pod-to-pod communication works. Service is an abstraction to route the traffic to any of the pods underneath, if label selectors match. We learned how service works with pod by iptables magic. We got to know how packet routes from external to a pod and the DNAT, un-DAT tricks. We also learned new API objects such as ingress, which allow us to use the URL path to route to different services in the backend. In the end, another object NetworkPolicy was introduced. It provides a second layer of security, acting as a software firewall rule. With network policy, we can make certain pods communicate only with certain pods. For example, only data retrieval service can talk to the database container. All of these things make Kubernetes more flexible, secure, and...