Ángel Guzmán MaesoandTianon Gravi
7ff358dc2d
Thanks to @tianon Co-authored-by: Tianon Gravi <admwiggin@gmail.com>
74 lines
2.8 KiB
Plaintext
74 lines
2.8 KiB
Plaintext
= docker-alpine
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:ao: alpinelinux.org
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:hubp: _/alpine
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:hub: https://hub.docker.com/r/{hubp}/
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image:https://img.shields.io/docker/stars/{hubp}.svg[link={hub}]
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image:https://img.shields.io/docker/pulls/{hubp}.svg[link={hub}]
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The official Docker image for https://{ao}[Alpine Linux].
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The image is only 5MB and has access to a package repository that is much more featureful than other BusyBox based images.
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== Why
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Docker images today are big.
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Usually much larger than they need to be.
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There are a lot of ways to make them smaller, but the Docker populace still jumps to the `ubuntu` base image for most projects.
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The size savings over `ubuntu` and other bases are huge:
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[source]
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----
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REPOSITORY TAG IMAGE ID CREATED SIZE
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alpine latest 961769676411 4 weeks ago 5.58MB
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ubuntu latest 2ca708c1c9cc 2 days ago 64.2MB
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debian latest c2c03a296d23 9 days ago 114MB
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centos latest 67fa590cfc1c 4 weeks ago 202MB
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----
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There are images such as `progrium/busybox` which get us close to a minimal container and package system, but these particular BusyBox builds piggyback on the OpenWRT package index, which is often lacking and not tailored towards generic everyday applications.
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Alpine Linux has a much more featureful and up to date https://pkgs.{ao}[Package Index]:
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[source]
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----
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$ docker run progrium/busybox opkg-install nodejs
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Unknown package 'nodejs'.
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Collected errors:
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* opkg_install_cmd: Cannot install package nodejs.
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$ docker run alpine apk add --no-cache nodejs
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fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz
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fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz
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(1/7) Installing ca-certificates (20190108-r0)
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(2/7) Installing c-ares (1.15.0-r0)
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(3/7) Installing libgcc (8.3.0-r0)
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(4/7) Installing http-parser (2.8.1-r0)
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(5/7) Installing libstdc++ (8.3.0-r0)
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(6/7) Installing libuv (1.23.2-r0)
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(7/7) Installing nodejs (10.14.2-r0)
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Executing busybox-1.29.3-r10.trigger
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Executing ca-certificates-20190108-r0.trigger
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OK: 31 MiB in 21 packages
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----
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This makes Alpine Linux a great image base for utilities, as well as production applications.
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https://www.{ao}/about/[Read more about Alpine Linux here] and it will become obvious how its mantra fits in right at home with Docker images.
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NOTE: All of the example outputs above were last generated/updated on May 3rd 2019.
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== Usage
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Stop doing this:
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[source, dockerfile]
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----
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FROM ubuntu:22.04
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RUN apt-get update -q \
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&& DEBIAN_FRONTEND=noninteractive apt-get install -qy mysql-client \
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&& apt-get clean \
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&& rm -rf /var/lib/apt
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ENTRYPOINT ["mysql"]
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----
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This took 28 seconds to build and yields a 169 MB image.
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Start doing this:
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[source, dockerfile]
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----
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FROM alpine:3.16
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RUN apk add --no-cache mysql-client
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ENTRYPOINT ["mysql"]
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----
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Only 4 seconds to build and results in a 41 MB image!
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