Kubernetes networking

In this section we’ll cover the following network-related topics:

• Kubernetes services
• The pod network
• Service registration and discovery

Kubernetes services

You already know that pods are typically deployed via higher-level controllers like the deployment controller and the statefulset controller. These implement cloud native features such as self-healing, autoscaling, rollouts, and rollbacks.

These features make individual pods extremely unreliable. Consider the following examples.

Every time a node or pod fails, the missing pod is replaced with a new pod with a new IP address. If a client was connecting directly to the failed pod, future connections will time-out and won’t re-establish to the new pod. Scale-up events add new pods with new IP addresses, whereas scale-down events remove pods. Again, clients connected to a pod that is removed as part of a scale-down operation will lose their connection. Finally, rolling out a new version...