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

Container runtimes

Containers run on physical servers, virtual machines, and cloud instances. As they all look the same to a container we’ll refer to them generically as nodes.

Every node that wants to run containers needs specialised software called a container runtime. This is responsible for downloading container images from registries, as well as creating, starting, stopping, and deleting containers on the node. Docker is the best-known container runtime, but lots of others exist.

Let’s revisit the workflow mentioned earlier to show where container runtimes fit in.

Developers write applications that get built into container images and stored in registries. To run a container, a node needs to download the image and start a container from it. The software that does this is the container runtime. The act of downloading a container image is usually referred to as pulling the image.

If you’ve worked with VMware, it might be helpful to compare container runtimes...