46 lines
1.5 KiB
Plaintext
46 lines
1.5 KiB
Plaintext
= Usage
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== Packages
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Replacing your current base image with the Docker Alpine Linux image usually requires updating the package names to the corresponding ones in the https://pkgs.alpinelinux.org[Alpine Linux package index].
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We use the `apk` command to manage packages.
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It works similarly to `apt` and `yum`.
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For example, installing the `nginx` package would be done by running `apk add --no-cache nginx`.
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The `--no-cache` argument prevents `apk` from caching the package index - something that would normally take up precious space, as well as go stale quickly.
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=== Example
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This is an example of a complete Dockerfile for `nginx`:
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[source, dockerfile]
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----
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FROM alpine
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RUN apk --no-cache add nginx
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EXPOSE 80
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CMD ["nginx", "-g", "daemon off;"]
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----
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=== Virtual Packages
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Another great `apk` feature is the concept of user-defined virtual packages.
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Packages added under a virtual package name can later be removed as one group.
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An example use-case would be removing all build dependencies at once, as in this example:
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[source, dockerfile]
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----
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FROM alpine
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WORKDIR /myapp
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COPY . /myapp
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RUN apk add --no-cache python py-pip openssl ca-certificates
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RUN apk add --no-cache --virtual build-dependencies python-dev build-base wget \
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&& pip install -r requirements.txt \
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&& python setup.py install \
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&& apk del build-dependencies
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CMD ["myapp", "start"]
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----
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// COMBAK: update docs link
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=== Further Details
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For further details on `apk` and how it's used, you can look at https://docs.alpinelinux.org/user-handbook/0.1a/Working/apk.html[Alpine's User Documentation] for it.
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