42 lines
1.8 KiB
Docker
42 lines
1.8 KiB
Docker
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% DOCKERFILE(1) Docker User Manuals
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% Zac Dover
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% May 2014
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# NAME
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Dockerfile - automate the steps of creating a Docker image
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# INTRODUCTION
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**Dockerfile** is a configuration file that automates the steps of creating a Docker image. Docker can act as a builder and can read instructions from **Dockerfile** to automate the steps that you would otherwise manually perform to create an image. To build an image from a source repository, create a description file called **Dockerfile** at the root of your repository. This file describes the steps that will be taken to assemble the image. When **Dockerfile** has been created, call **docker build** with the path of the source repository as the argument.
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# SYNOPSIS
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INSTRUCTION arguments
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For example:
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FROM image
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# DESCRIPTION
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Dockerfile is a file that automates the steps of creating a Docker image.
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# USAGE
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$ sudo docker build .
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-- runs the steps and commits them, building a final image
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The path to the source repository defines where to find the context of the build.
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The build is run by the docker daemon, not the CLI. The whole context must be
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transferred to the daemon. The Docker CLI reports "Uploading context" when the
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context is sent to the daemon.
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$ sudo docker build -t repository/tag .
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-- specifies a repository and tag at which to save the new image if the build succeeds.
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The Docker daemon runs the steps one-by-one, commiting the result to a new image
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if necessary before finally outputting the ID of the new image. The Docker
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daemon automatically cleans up the context it is given.
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Docker re-uses intermediate images whenever possible. This significantly accelerates the *docker build* process.
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# HISTORY
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May 2014, Compiled by Zac Dover (zdover at redhat dot com) based on docker.io Dockerfile documentation.
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