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: Highly-coupled container-to-container communications: this is solved by Pods and localhost communications. Pod-to-Pod communications: this is the primary focus of this document. Pod-to-Service communications: this is covered by Services. External-to-Service communications: this is also covered by Services. Kubernetes is all about sharing machines among applications.