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Learning Docker

You're reading from   Learning Docker Optimize the power of Docker to run your applications quickly and easily

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Product type Paperback
Published in Jun 2015
Publisher
ISBN-13 9781784397937
Length 240 pages
Edition 1st Edition
Tools
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Toc

Table of Contents (13) Chapters Close

Preface 1. Getting Started with Docker 2. Handling Docker Containers FREE CHAPTER 3. Building Images 4. Publishing Images 5. Running Your Private Docker Infrastructure 6. Running Services in a Container 7. Sharing Data with Containers 8. Orchestrating Containers 9. Testing with Docker 10. Debugging Containers 11. Securing Docker Containers Index

A quick overview of the Dockerfile's syntax

In this section, we will explain the syntax or the format of Dockerfile. A Dockerfile is made up of instructions, comments, and empty lines, as shown here:

# Comment

INSTRUCTION arguments

The instruction line of Dockerfile is made up of two components, where the instruction line begins with the instruction itself, which is followed by the arguments for the instruction. The instruction could be written in any case, in other words, it is case-insensitive. However, the standard practice or convention is to use uppercase in order to differentiate it from the arguments. Let's take another look at the content of Dockerfile in our previous example:

FROM busybox:latest
CMD echo Hello World!!

Here, FROM is an instruction which has taken busybox:latest as an argument, and CMD is an instruction which has taken echo Hello World!! as an argument.

The comment line in Dockerfile must begin with the # symbol. The # symbol after an instruction is considered...

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