Book Image

Docker Certified Associate (DCA): Exam Guide

By : Francisco Javier Ramírez Urea
Book Image

Docker Certified Associate (DCA): Exam Guide

By: Francisco Javier Ramírez Urea

Overview of this book

Developers have changed their deployment artifacts from application binaries to container images, and they now need to build container-based applications as containers are part of their new development workflow. This Docker book is designed to help you learn about the management and administrative tasks of the Containers as a Service (CaaS) platform. The book starts by getting you up and running with the key concepts of containers and microservices. You'll then cover different orchestration strategies and environments, along with exploring the Docker Enterprise platform. As you advance, the book will show you how to deploy secure, production-ready, container-based applications in Docker Enterprise environments. Later, you'll delve into each Docker Enterprise component and learn all about CaaS management. Throughout the book, you'll encounter important exam-specific topics, along with sample questions and detailed answers that will help you prepare effectively for the exam. By the end of this Docker containers book, you'll have learned how to efficiently deploy and manage container-based environments in production, and you will have the skills and knowledge you need to pass the DCA exam.
Table of Contents (22 chapters)
1
Section 1 - Key Container Concepts
8
Section 2 - Container Orchestration
12
Section 3 - Docker Enterprise
17
Section 4 - Preparing for the Docker Certified Associate Exam

Customizing images with docker-compose

Building applications using docker-compose is very useful because we can use it for creating all the images in Docker Swarm or Kubernetes environments. We just need a docker-compose file definition and the application components' code.

We have been using a static docker-compose file definition, but in many cases, we will use some variables to fulfill their values for specific needs. In fact, we could use variables in Dockerfiles as well, to complete the dynamic configurations at all levels.

Let's introduce some variables to our application's docker-compose.yaml file (we do this to allow different behaviors):

version: "3.7"

services:
lb:
build:
context: ./simplestlb
args:
alpineversion: "latest"
dockerfile: Dockerfile.custom
labels:
org.codegazers.dscription: "Test image"
image: ${dockerhubid}/simplest-lab:simplestlb
environment:
- APPLICATION_ALIAS=simplestapp...