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Replaced curly quotes in command samples with regular quotes

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imedqq 2018-10-31 14:22:57 -04:00
parent 90af0bc8d5
commit 17c97dab59
1 changed files with 12 additions and 12 deletions
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develop/develop-images/dockerfile_best-practices.md
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@ -1,4 +1,4 @@
--- ---
description: Hints, tips and guidelines for writing clean, reliable Dockerfiles description: Hints, tips and guidelines for writing clean, reliable Dockerfiles
keywords: parent image, images, dockerfile, best practices, hub, official repo keywords: parent image, images, dockerfile, best practices, hub, official repo
redirect_from: redirect_from:
@ -49,7 +49,7 @@ For more on image layers (and how Docker builds and stores images), see
### Create ephemeral containers ### Create ephemeral containers
The image defined by your `Dockerfile` should generate containers that are as The image defined by your `Dockerfile` should generate containers that are as
ephemeral as possible. By “ephemeral,” we mean that the container can be stopped ephemeral as possible. By "ephemeral," we mean that the container can be stopped
and destroyed, then rebuilt and replaced with an absolute minimum set up and and destroyed, then rebuilt and replaced with an absolute minimum set up and
configuration. configuration.
@ -191,8 +191,8 @@ CMD ["--help"]
### Don't install unnecessary packages ### Don't install unnecessary packages
To reduce complexity, dependencies, file sizes, and build times, avoid To reduce complexity, dependencies, file sizes, and build times, avoid
installing extra or unnecessary packages just because they might be “nice to installing extra or unnecessary packages just because they might be "nice to
have.” For example, you don’t need to include a text editor in a database image. have." For example, you don’t need to include a text editor in a database image.
### Decouple applications ### Decouple applications
@ -358,7 +358,7 @@ Probably the most common use-case for `RUN` is an application of `apt-get`.
Because it installs packages, the `RUN apt-get` command has several gotchas to Because it installs packages, the `RUN apt-get` command has several gotchas to
look out for. look out for.
Avoid `RUN apt-get upgrade` and `dist-upgrade`, as many of the “essential” Avoid `RUN apt-get upgrade` and `dist-upgrade`, as many of the "essential"
packages from the parent images cannot upgrade inside an packages from the parent images cannot upgrade inside an
[unprivileged container](/engine/reference/run.md#security-configuration). If a package [unprivileged container](/engine/reference/run.md#security-configuration). If a package
contained in the parent image is out-of-date, contact its maintainers. If you contained in the parent image is out-of-date, contact its maintainers. If you
@ -477,16 +477,16 @@ RUN set -o pipefail && wget -O - https://some.site | wc -l > /number
The `CMD` instruction should be used to run the software contained by your The `CMD` instruction should be used to run the software contained by your
image, along with any arguments. `CMD` should almost always be used in the form image, along with any arguments. `CMD` should almost always be used in the form
of `CMD [“executable”, “param1”, “param2”…]`. Thus, if the image is for a of `CMD ["executable", "param1", "param2"…]`. Thus, if the image is for a
service, such as Apache and Rails, you would run something like `CMD service, such as Apache and Rails, you would run something like `CMD
["apache2","-DFOREGROUND"]`. Indeed, this form of the instruction is recommended ["apache2","-DFOREGROUND"]`. Indeed, this form of the instruction is recommended
for any service-based image. for any service-based image.
In most other cases, `CMD` should be given an interactive shell, such as bash, In most other cases, `CMD` should be given an interactive shell, such as bash,
python and perl. For example, `CMD ["perl", "-de0"]`, `CMD ["python"]`, or `CMD python and perl. For example, `CMD ["perl", "-de0"]`, `CMD ["python"]`, or `CMD
[“php”, “-a”]`. Using this form means that when you execute something like ["php", "-a"]`. Using this form means that when you execute something like
`docker run -it python`, you’ll get dropped into a usable shell, ready to go. `docker run -it python`, you’ll get dropped into a usable shell, ready to go.
`CMD` should rarely be used in the manner of `CMD [“param”, “param”]` in `CMD` should rarely be used in the manner of `CMD ["param", "param"]` in
conjunction with [`ENTRYPOINT`](/engine/reference/builder.md#entrypoint), unless conjunction with [`ENTRYPOINT`](/engine/reference/builder.md#entrypoint), unless
you and your expected users are already quite familiar with how `ENTRYPOINT` you and your expected users are already quite familiar with how `ENTRYPOINT`
works. works.
@ -512,7 +512,7 @@ the recipient container back to the source (ie, `MYSQL_PORT_3306_TCP`).
To make new software easier to run, you can use `ENV` to update the To make new software easier to run, you can use `ENV` to update the
`PATH` environment variable for the software your container installs. For `PATH` environment variable for the software your container installs. For
example, `ENV PATH /usr/local/nginx/bin:$PATH` ensures that `CMD [“nginx”]` example, `ENV PATH /usr/local/nginx/bin:$PATH` ensures that `CMD ["nginx"]`
just works. just works.
The `ENV` instruction is also useful for providing required environment The `ENV` instruction is also useful for providing required environment
@ -714,7 +714,7 @@ like `RUN groupadd -r postgres && useradd --no-log-init -r -g postgres postgres`
> Consider an explicit UID/GID > Consider an explicit UID/GID
> >
> Users and groups in an image are assigned a non-deterministic UID/GID in that > Users and groups in an image are assigned a non-deterministic UID/GID in that
> the “next” UID/GID is assigned regardless of image rebuilds. So, if it’s > the "next" UID/GID is assigned regardless of image rebuilds. So, if it’s
> critical, you should assign an explicit UID/GID. > critical, you should assign an explicit UID/GID.
> Due to an [unresolved bug](https://github.com/golang/go/issues/13548) in the > Due to an [unresolved bug](https://github.com/golang/go/issues/13548) in the
@ -727,7 +727,7 @@ like `RUN groupadd -r postgres && useradd --no-log-init -r -g postgres postgres`
Avoid installing or using `sudo` as it has unpredictable TTY and Avoid installing or using `sudo` as it has unpredictable TTY and
signal-forwarding behavior that can cause problems. If you absolutely need signal-forwarding behavior that can cause problems. If you absolutely need
functionality similar to `sudo`, such as initializing the daemon as `root` but functionality similar to `sudo`, such as initializing the daemon as `root` but
running it as non-`root`), consider using [“gosu”](https://github.com/tianon/gosu). running it as non-`root`), consider using ["gosu"](https://github.com/tianon/gosu).
Lastly, to reduce layers and complexity, avoid switching `USER` back and forth Lastly, to reduce layers and complexity, avoid switching `USER` back and forth
frequently. frequently.
@ -761,7 +761,7 @@ builds arbitrary user software written in that language within the
Images built from `ONBUILD` should get a separate tag, for example: Images built from `ONBUILD` should get a separate tag, for example:
`ruby:1.9-onbuild` or `ruby:2.0-onbuild`. `ruby:1.9-onbuild` or `ruby:2.0-onbuild`.
Be careful when putting `ADD` or `COPY` in `ONBUILD`. The “onbuild” image Be careful when putting `ADD` or `COPY` in `ONBUILD`. The "onbuild" image
fails catastrophically if the new build's context is missing the resource being fails catastrophically if the new build's context is missing the resource being
added. Adding a separate tag, as recommended above, helps mitigate this by added. Adding a separate tag, as recommended above, helps mitigate this by
allowing the `Dockerfile` author to make a choice. allowing the `Dockerfile` author to make a choice.