Book Image

Becoming KCNA Certified

By : Dmitry Galkin
Book Image

Becoming KCNA Certified

By: Dmitry Galkin

Overview of this book

The job market related to the cloud and cloud-native technologies is both growing and becoming increasingly competitive, making certifications like KCNA a great way to stand out from the crowd and learn about the latest advancements in cloud technologies. Becoming KCNA Certified doesn't just give you the practical skills needed to deploy and connect applications in Kubernetes, but it also prepares you to pass the Kubernetes and Cloud Native Associate (KCNA) exam on your first attempt. The book starts by introducing you to cloud-native computing, containers, and Kubernetes through practical examples, allowing you to test the theory out for yourself. You'll learn how to configure and provide storage for your Kubernetes-managed applications and explore the principles of modern cloud-native architecture and application delivery, giving you a well-rounded view of the subject. Once you've been through the theoretical and practical aspects of the book, you'll get the chance to test what you’ve learnt with two mock exams, with explanations of the answers, so you'll be well-prepared to appear for the KCNA exam. By the end of this Kubernetes book, you'll have everything you need to pass the KCNA exam and forge a career in Kubernetes and cloud-native computing.
Table of Contents (22 chapters)
1
Part 1: The Cloud Era
4
Part 2: Performing Container Orchestration
7
Part 3: Learning Kubernetes Fundamentals
12
Part 4: Exploring Cloud Native
16
Part 5: KCNA Exam and Next Steps

Building container images

Now that we know how to start containers and pull images, we’ll learn what should be done to create new container images. Since the image layer is immutable, you can create new images with the software of your choice to build an image by adding new layers on top of existing ones. There are two ways this can be done with Docker:

  • Interactively
  • Using Dockerfile

The interactive way is to create an image from an existing container. Let’s say you start a container with the Ubuntu 22.04 environment, install additional packages, and expose port 80. To create a new image, we can use the docker commit command:

 $ docker commit CONTAINER_ID [REPOSITORY[:TAG]] 

The image name will be in the REPOSITORY:TAG format. If no tag is given, then latest will be added automatically. If no repository was specified, the image name will be a unique identifier (UUID). The tag, as well as the name (which is the same as the image repository’...