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

Chapter 3

  1. a and c: build is only available for image objects, and destroy does not exist for any object.
  2. b: This is not true. The Docker daemon will wait a defined amount of time (10 seconds, by default) before issuing a SIGKILL signal to the container's main process.
  3. b: docker kill will immediately send a SIGKILL signal to the container's main process. Not all processes will be killed if they were executed in the background; for example, inside the container. It can leave zombie processes if they do not have parent-child dependencies. As we learned, containers must be removed by hand and docker kill will not remove them.
  1. b: docker container update will only change the container restart policy and its access to host resources.
  1. c: We have launched a privileged container; therefore no resource limits will be applied, although we have used -memory to confine memory usage. The privileged mode does not affect the filesystem. It will only modify the main process behavior, but...