Book Image

The KCNA Book

By : Nigel Poulton
Book Image

The KCNA Book

By: Nigel Poulton

Overview of this book

There is a huge benefit in building small, specialized, single-purpose apps that can self-heal, auto scale, and update regularly without needing downtime. Kubernetes and cloud-native technologies come in handy in building such apps. Possessing the knowledge and skills to leverage Kubernetes can positively enhance possibilities in favor of architects who specialize in cloud-native microservices applications. ‘The KCNA Book’ is designed to help those working in technology with a passion to become certified in the Kubernetes and Cloud-Native Associate Exam. You will learn about containerization, microservices, and cloud-native architecture. You will learn about Kubernetes fundamentals and container orchestration. The book also sheds light on cloud-native application delivery and observability. It focuses on the KCNA exam domains and competencies, which can be applied to the sample test included in the book. Put your knowledge to the test and enhance your skills with the all-encompassing topic coverage. Upon completion, you will begin your journey to get the best roles, projects, and organizations with this exam-oriented book.
Table of Contents (12 chapters)
8: Sample test
Appendix B: Sample Test answers

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...