alpinelinux / Docker Alpine

= docker-alpine

:ao: alpinelinux.org :hubp: _/alpine :hub: https://hub.docker.com/r/{hubp}/

image:https://img.shields.io/docker/stars/{hubp}.svg[link={hub}] image:https://img.shields.io/docker/pulls/{hubp}.svg[link={hub}]

The official Docker image for https://{ao}[Alpine Linux]. The image is only 5MB and has access to a package repository that is much more featureful than other BusyBox based images.

== Why Docker images today are big. Usually much larger than they need to be. There are a lot of ways to make them smaller, but the Docker populace still jumps to the ubuntu base image for most projects. The size savings over ubuntu and other bases are huge: [source]

REPOSITORY TAG IMAGE ID CREATED SIZE alpine latest 961769676411 4 weeks ago 5.58MB ubuntu latest 2ca708c1c9cc 2 days ago 64.2MB debian latest c2c03a296d23 9 days ago 114MB centos latest 67fa590cfc1c 4 weeks ago 202MB

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. Alpine Linux has a much more featureful and up to date https://pkgs.{ao}[Package Index]: [source]

$ docker run progrium/busybox opkg-install nodejs Unknown package 'nodejs'. Collected errors:

• opkg_install_cmd: Cannot install package nodejs.

$ docker run alpine apk add --no-cache nodejs fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz (1/7) Installing ca-certificates (20190108-r0) (2/7) Installing c-ares (1.15.0-r0) (3/7) Installing libgcc (8.3.0-r0) (4/7) Installing http-parser (2.8.1-r0) (5/7) Installing libstdc++ (8.3.0-r0) (6/7) Installing libuv (1.23.2-r0) (7/7) Installing nodejs (10.14.2-r0) Executing busybox-1.29.3-r10.trigger Executing ca-certificates-20190108-r0.trigger OK: 31 MiB in 21 packages

This makes Alpine Linux a great image base for utilities, as well as production applications. 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.

NOTE: All of the example outputs above were last generated/updated on May 3rd 2019.

== Usage Stop doing this: [source, dockerfile]

FROM ubuntu-debootstrap:14.04 RUN apt-get update -q
&& DEBIAN_FRONTEND=noninteractive apt-get install -qy mysql-client
&& apt-get clean
&& rm -rf /var/lib/apt ENTRYPOINT ["mysql"]

This took 28 seconds to build and yields a 169 MB image. Start doing this: [source, dockerfile]

FROM alpine:3.9 RUN apk add --no-cache mysql-client ENTRYPOINT ["mysql"]

Only 4 seconds to build and results in a 41 MB image!