diff --git a/docs/reference/builder.md b/docs/reference/builder.md index b3010a47d4..68b2db1f63 100644 --- a/docs/reference/builder.md +++ b/docs/reference/builder.md @@ -1286,12 +1286,12 @@ to create the directory in the Dockerfile. For example: ARG [=] The `ARG` instruction defines a variable that users can pass at build-time to -the builder with the `docker build` command using the -`--build-arg =` flag. If a user specifies a build argument -that was not defined in the Dockerfile, the build outputs an error. +the builder with the `docker build` command using the `--build-arg +=` flag. If a user specifies a build argument that was not +defined in the Dockerfile, the build outputs a warning. ``` -One or more build-args were not consumed, failing build. +[Warning] One or more build-args [foo] were not consumed. ``` The Dockerfile author can define a single variable by specifying `ARG` once or many diff --git a/man/Dockerfile.5.md b/man/Dockerfile.5.md index df69935397..5191b1930a 100644 --- a/man/Dockerfile.5.md +++ b/man/Dockerfile.5.md @@ -26,7 +26,7 @@ For example: # DESCRIPTION -A Dockerfile is a file that automates the steps of creating a Docker image. +A Dockerfile is a file that automates the steps of creating a Docker image. A Dockerfile is similar to a Makefile. # USAGE @@ -71,10 +71,10 @@ A Dockerfile is similar to a Makefile. multiple images. Make a note of the last image ID output by the commit before each new **FROM** command. - -- If no tag is given to the **FROM** instruction, Docker applies the + -- If no tag is given to the **FROM** instruction, Docker applies the `latest` tag. If the used tag does not exist, an error is returned. - -- If no digest is given to the **FROM** instruction, Docker applies the + -- If no digest is given to the **FROM** instruction, Docker applies the `latest` tag. If the used tag does not exist, an error is returned. **MAINTAINER** @@ -148,7 +148,7 @@ A Dockerfile is similar to a Makefile. ``` -- To make the container run the same executable every time, use **ENTRYPOINT** in - combination with **CMD**. + combination with **CMD**. If the user specifies arguments to `docker run`, the specified commands override the default in **CMD**. Do not confuse **RUN** with **CMD**. **RUN** runs a command and commits the result. @@ -156,7 +156,7 @@ A Dockerfile is similar to a Makefile. the image. **LABEL** - -- `LABEL = [= ...]`or + -- `LABEL = [= ...]`or ``` LABEL [ ] LABEL [ ] @@ -176,8 +176,8 @@ A Dockerfile is similar to a Makefile. ``` An image can have more than one label. To specify multiple labels, separate - each key-value pair by a space. - + each key-value pair by a space. + Labels are additive including `LABEL`s in `FROM` images. As the system encounters and then applies a new label, new `key`s override any previous labels with identical keys. @@ -194,7 +194,7 @@ A Dockerfile is similar to a Makefile. **ENV** -- `ENV ` The **ENV** instruction sets the environment variable to - the value ``. This value is passed to all future + the value ``. This value is passed to all future **RUN**, **ENTRYPOINT**, and **CMD** instructions. This is functionally equivalent to prefixing the command with `=`. The environment variables that are set with **ENV** persist when a container is run @@ -243,7 +243,7 @@ A Dockerfile is similar to a Makefile. being built (the context of the build) or a remote file URL. The `` is an absolute path, or a path relative to **WORKDIR**, into which the source will be copied inside the target container. If you **COPY** an archive file it will - land in the container exactly as it appears in the build context without any + land in the container exactly as it appears in the build context without any attempt to unpack it. All new files and directories are created with mode **0755** and with the uid and gid of **0**. @@ -326,10 +326,10 @@ A Dockerfile is similar to a Makefile. The `ARG` instruction defines a variable that users can pass at build-time to the builder with the `docker build` command using the `--build-arg =` flag. If a user specifies a build argument that was not - defined in the Dockerfile, the build outputs an error. + defined in the Dockerfile, the build outputs a warning. ``` - One or more build-args were not consumed, failing build. + [Warning] One or more build-args [foo] were not consumed ``` The Dockerfile author can define a single variable by specifying `ARG` once or many @@ -454,7 +454,7 @@ A Dockerfile is similar to a Makefile. you are defining an image to use as a base for building other images. For example, if you are defining an application build environment or a daemon that is customized with a user-specific configuration. - + Consider an image intended as a reusable python application builder. It must add application source code to a particular directory, and might need a build script called after that. You can't just call **ADD** and **RUN** now, because @@ -470,4 +470,5 @@ A Dockerfile is similar to a Makefile. # HISTORY *May 2014, Compiled by Zac Dover (zdover at redhat dot com) based on docker.com Dockerfile documentation. *Feb 2015, updated by Brian Goff (cpuguy83@gmail.com) for readability -*Sept 2015, updated by Sally O'Malley (somalley@redhat.com) +*Sept 2015, updated by Sally O'Malley (somalley@redhat.com) +*Oct 2016, updated by Addam Hardy (addam.hardy@gmail.com)