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

Containers and pods

Let’s clear up some terminology before getting into the detail.

We sometimes use the terms container and pod to mean the same thing. However, a pod is actually a thin wrapper around one or more containers and is a mandatory requirement for any container that wants to run on Kubernetes. This means containers must be wrapped in a pod if they want to run on Kubernetes. The following extremely simple YAML file defines a pod with a single container.

1  apiVersion: v1
2  kind: Pod
3  metadata:
4    name: kcna-pod
5    labels:
6      project: kcna-book
7  spec:
8    containers:     <<==== Container is defined below here
9      - name: kcna-container
10       image: <container-image-goes-here>

Lines 1-7 give the pod and name and a label. Lines 8-10 show the container definition embedded within the overall pod definition. As the container is embedded within the pod definition, we say the pod “wraps the container”.

As well as...