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)
9
8: Sample test
Appendix B: Sample Test answers

Augmenting pods

You’ve just learned that pods wrap one or more containers and add capabilities. However, pods don’t self-heal, they don’t autoscale, and they don’t do things like zero-downtime rollouts. Kubernetes has higher-level controllers that wrap around pods and implement these features. As a result, you’ll almost always deploy pods via higher level controllers such as deployments and statefulsets.

You’ll learn more about controllers later in the chapter. But for now, let’s consider a simple example of deploying a stateless web server.

Your development team writes a stateless web app and packages it as a container. You know you need 5 instances to meet expected demand, and as you’re running a Kubernetes environment you need to wrap each container in a pod. However, pods aren’t resilient. For example, if you deploy 5 standalone pods and a node hosting 2 of them fails, there’s no intelligence to recreate them...