Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Beginning DevOps with Docker
Beginning DevOps with Docker

Beginning DevOps with Docker: Automate the deployment of your environment with the power of the Docker toolchain

eBook
€6.99 €10.99
Paperback
€12.99
Subscription
Free Trial
Renews at €18.99p/m

What do you get with a Packt Subscription?

Free for first 7 days. $19.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing
Table of content icon View table of contents Preview book icon Preview Book

Beginning DevOps with Docker

Chapter 2. Application Container Management

In this lesson, we will scale one of the containers we built into a multi-tier setup. This will involve splitting the application into different logical sections. For example, we could have an application running on a Docker container and the application's data in a separate database container; however, both should work as a single entity. For this, we will use Docker's tool for running multi-container applications. The tool goes by the name docker-compose. In summary, docker-compose is the tool used for defining and running multi-container Docker applications.

Lesson Objectives

By the end of this lesson, you will be able to:

  • Get an overview of a multi-container application setup
  • Work through the docker-compose file and CLI
  • Manage multiple containers and distributed application bundles
  • Set up a network with docker-compose
  • Handle and debug the different application layers

The docker-compose Tool

Let's begin the lesson by looking at what a multi-container setup is, why it is important, and how Docker, with the tool docker-compose, works like a charm in such scenarios.

We have recently been introduced to how applications work, with their separate elements: frontend, backend, and database.

To run such a multi-tier application using Docker, one would need to run the following commands to spin up the containers in different terminal sessions:

- docker run <front-end>
- docker run <back-end>
- docker run <database>

Note

You can run docker run with (-d) as detached to prevent us from running the three commands in separate sessions, for example: docker run <front-end> -d

That said, it even becomes particularly tasking linking different containers (networking).

docker-compose comes in to save the day. We can define and run multi-containers from one file - docker-compose.yml. In the following topics, we'll discuss this further. First,...

Overview of a Multi-Container Application Setup

In the previous lesson, we introduced Docker and containerization. We ran sample Python and JavaScript scripts as demonstrations of how applications can be containerized and how images can be built. We are now ready to run an application that goes beyond that.

In a Dockerfile, every line describes a layer. The union filesystem used in Docker allows different directories to transparently overlay, forming a single, coherent filesystem. The foundational layer is always an image which you build upon. Each additional line with a command, say, RUN, CMD, and so on, adds a layer to it. The advantage of layers is that as long as the layer has not been modified, it will not bother building that part of the image. Secondly, as an image is pulled from a Docker image registry, it is pulled in layers, therefore mitigating issues such as connection cuts during pulling and pushing of images.

Many applications are built under a common structure: frontend, backend...

Managing Multiple Containers and Distributed Application Bundles

This is the docker-compose.yml for running a Django application. A similar application can be found in the docker-compose documentation under the Django example.

Download the Django example from: ttps://docs.docker.com/compose/django/:

Managing Multiple Containers and Distributed Application Bundles

Note

Refer the complete code placed at Code/Lesson-2/django-docker-compose.yml.

Go to https://goo.gl/H624J1 to access the code.

Improve a Docker Workflow

To give more context on how docker-compose is involved and how it improves a Docker workflow.

  1. Create a new directory and name it django_docker.
  2. In the django-docker directory, create a new docker-compose.yml and add the information in the figure above, or in the django-docker-compose.yml script provided.
  3. Create a new Dockerfile and add the content in the Dockerfile script provided.
  4. Create a requirements file; simply copy the django-requirements.txt file provided.
  5. Run docker-compose up and observe the logs.

Notice that we are able to spin up both containers...

Networking with docker-compose

By default, docker-compose sets up a single network for your application(s) where each container can reach and discover other containers.

The network is given a name based on the name of the directory it lives in. Thus, if your directory is called py_docker, when your run docker-compose up, the network created is called py_docker_default.

We mentioned ports in the previous topic, when creating the WordPress container. To explain networking better, we'll use the docker-compose.yml used to spin up a WordPress application:

Networking with docker-compose

In this file, we have two services: db and wordpress.

In the WordPress service, we have the ports option mapping port 80 to port 8000. No wonder, the WordPress app runs on 0.0.0.0:8000 on our browsers.

The ports option is not in the db service. However, if you go to the docker hub page for mysql, you'll notice that port 3306 is exposed. This is the standard port for MySQL. You can obtain more information on MySQL from: https://hub.docker...

Summary

In this lesson, we have done the following:

  • Discussed and displayed a multi-container setup
  • Walked through docker-compose commands to build and run multiple containers in a parallel manner
  • Gained a high-level understanding of networking containers and how data is persisted in a container from local machines
  • Built and run applications without even setting them up, via Docker Hub
Left arrow icon Right arrow icon

Key benefits

  • Learn how to structure your own Docker containers
  • Create and manage multiple configuration images
  • Understand how to scale and deploy bespoke environments

Description

Making sure that your application runs across different systems as intended is quickly becoming a standard development requirement. With Docker, you can ensure that what you build will behave the way you expect it to, regardless of where it's deployed. By guiding you through Docker from start to finish (from installation, to the Docker Registry, all the way through to working with Docker Swarms), we’ll equip you with the skills you need to migrate your workflow to Docker with complete confidence.

Who is this book for?

This book is ideal for developers, system architects and site reliability engineers (SREs) who wish to adopt a Docker-based workflow for consistency, speed and isolation of system resources within their applications. You’ll need to be comfortable working with the command line.

What you will learn

  • Learn to design and build containers for different kinds of applications
  • Create a testing environment to identify issues that may cause production deployments to fail
  • Discover how you can correctly structure and manage a multi-tier environment
  • Run, debug, and experiment with example applications in Docker containers

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : May 29, 2018
Length: 96 pages
Edition : 1st
Language : English
ISBN-13 : 9781789532401
Concepts :
Tools :

What do you get with a Packt Subscription?

Free for first 7 days. $19.99 p/m after that. Cancel any time!
Product feature icon Unlimited ad-free access to the largest independent learning library in tech. Access this title and thousands more!
Product feature icon 50+ new titles added per month, including many first-to-market concepts and exclusive early access to books as they are being written.
Product feature icon Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.
Product feature icon Thousands of reference materials covering every tech concept you need to stay up to date.
Subscribe now
View plans & pricing

Product Details

Publication date : May 29, 2018
Length: 96 pages
Edition : 1st
Language : English
ISBN-13 : 9781789532401
Concepts :
Tools :

Packt Subscriptions

See our plans and pricing
Modal Close icon
€18.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
€189.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts
€264.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total 82.97
Practical DevOps, Second Edition
€36.99
Beginning DevOps with Docker
€12.99
Learn Docker - Fundamentals of Docker 18.x
€32.99
Total 82.97 Stars icon
Banner background image

Table of Contents

4 Chapters
1. Images and Containers Chevron down icon Chevron up icon
2. Application Container Management Chevron down icon Chevron up icon
3. Orchestration and Delivery Chevron down icon Chevron up icon
Index Chevron down icon Chevron up icon

Customer reviews

Top Reviews
Rating distribution
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.9
(7 Ratings)
5 star 71.4%
4 star 0%
3 star 0%
2 star 0%
1 star 28.6%
Filter icon Filter
Top Reviews

Filter reviews by




Rohith Sep 21, 2023
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Subscriber review Packt
Gary Waltman Jul 07, 2019
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Easy read
Amazon Verified review Amazon
Amazon Customer Jun 14, 2018
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Excellent book.
Amazon Verified review Amazon
Dominic Motuka Jul 09, 2018
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Joseph has a solid grasp of the subject and understands that DevOps is more than just a series of scripts written and maintained by the (mostly) operations staff that tries to run with DevOps. Docker has been introduced to us ( the readers ) in a simple way.Well written and nicely illustrated with color images. This is an excellent introduction to Docker.
Amazon Verified review Amazon
NdagiStanley Aug 22, 2018
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Beginning DevOps with Docker is a must-read for individuals who expect proper code and written analogies that will enhance their understanding of the overall use of docker in DevOps. The docker commands are well explained, everything to get you from beginner to guru.
Amazon Verified review Amazon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is included in a Packt subscription? Chevron down icon Chevron up icon

A subscription provides you with full access to view all Packt and licnesed content online, this includes exclusive access to Early Access titles. Depending on the tier chosen you can also earn credits and discounts to use for owning content

How can I cancel my subscription? Chevron down icon Chevron up icon

To cancel your subscription with us simply go to the account page - found in the top right of the page or at https://subscription.packtpub.com/my-account/subscription - From here you will see the ‘cancel subscription’ button in the grey box with your subscription information in.

What are credits? Chevron down icon Chevron up icon

Credits can be earned from reading 40 section of any title within the payment cycle - a month starting from the day of subscription payment. You also earn a Credit every month if you subscribe to our annual or 18 month plans. Credits can be used to buy books DRM free, the same way that you would pay for a book. Your credits can be found in the subscription homepage - subscription.packtpub.com - clicking on ‘the my’ library dropdown and selecting ‘credits’.

What happens if an Early Access Course is cancelled? Chevron down icon Chevron up icon

Projects are rarely cancelled, but sometimes it's unavoidable. If an Early Access course is cancelled or excessively delayed, you can exchange your purchase for another course. For further details, please contact us here.

Where can I send feedback about an Early Access title? Chevron down icon Chevron up icon

If you have any feedback about the product you're reading, or Early Access in general, then please fill out a contact form here and we'll make sure the feedback gets to the right team. 

Can I download the code files for Early Access titles? Chevron down icon Chevron up icon

We try to ensure that all books in Early Access have code available to use, download, and fork on GitHub. This helps us be more agile in the development of the book, and helps keep the often changing code base of new versions and new technologies as up to date as possible. Unfortunately, however, there will be rare cases when it is not possible for us to have downloadable code samples available until publication.

When we publish the book, the code files will also be available to download from the Packt website.

How accurate is the publication date? Chevron down icon Chevron up icon

The publication date is as accurate as we can be at any point in the project. Unfortunately, delays can happen. Often those delays are out of our control, such as changes to the technology code base or delays in the tech release. We do our best to give you an accurate estimate of the publication date at any given time, and as more chapters are delivered, the more accurate the delivery date will become.

How will I know when new chapters are ready? Chevron down icon Chevron up icon

We'll let you know every time there has been an update to a course that you've bought in Early Access. You'll get an email to let you know there has been a new chapter, or a change to a previous chapter. The new chapters are automatically added to your account, so you can also check back there any time you're ready and download or read them online.

I am a Packt subscriber, do I get Early Access? Chevron down icon Chevron up icon

Yes, all Early Access content is fully available through your subscription. You will need to have a paid for or active trial subscription in order to access all titles.

How is Early Access delivered? Chevron down icon Chevron up icon

Early Access is currently only available as a PDF or through our online reader. As we make changes or add new chapters, the files in your Packt account will be updated so you can download them again or view them online immediately.

How do I buy Early Access content? Chevron down icon Chevron up icon

Early Access is a way of us getting our content to you quicker, but the method of buying the Early Access course is still the same. Just find the course you want to buy, go through the check-out steps, and you’ll get a confirmation email from us with information and a link to the relevant Early Access courses.

What is Early Access? Chevron down icon Chevron up icon

Keeping up to date with the latest technology is difficult; new versions, new frameworks, new techniques. This feature gives you a head-start to our content, as it's being created. With Early Access you'll receive each chapter as it's written, and get regular updates throughout the product's development, as well as the final course as soon as it's ready.We created Early Access as a means of giving you the information you need, as soon as it's available. As we go through the process of developing a course, 99% of it can be ready but we can't publish until that last 1% falls in to place. Early Access helps to unlock the potential of our content early, to help you start your learning when you need it most. You not only get access to every chapter as it's delivered, edited, and updated, but you'll also get the finalized, DRM-free product to download in any format you want when it's published. As a member of Packt, you'll also be eligible for our exclusive offers, including a free course every day, and discounts on new and popular titles.