114 lines
2.5 KiB
Markdown
114 lines
2.5 KiB
Markdown
# A simple base docker image for Alpine.
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20230410
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My Alpine Docker Images are pretty standard. Nothing specific here.
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## Alpine Docker Image
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### Setup FROM and enable a version choice.
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First let's set the where we'll pull from. I use `podman` and `docker` equally, so on I give the full path to the FROM image.
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An `ARG` for the version, `VER` is there. This can be overridden with `--build-arg 'VER=<version>'`.
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```
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<<base.image>>=
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ARG VER=latest
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FROM docker.io/alpine:${VER}
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@ % def VER
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```
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### Setup user specific arguments.
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Setup a base username, uid, gid, and work directory with some defaults. All of these can be overridden with `-build-arg "ARG=VALUE"`.
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```
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<<base.userargs>>=
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ARG baseUSER="mat.kovach"
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ARG baseUID=5000
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ARG baseGID=5000
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ARG baseDIR="/work"
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@
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```
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### Add user and work directory
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You'll need to be careful here to not change a current directory. For example, do not set baseDIR="/bin".
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Add the group, user, (with the home directory of the user ad the work directory) and insure the proper ownership on the work directory.
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*Alpine requies you add the `shadow` package before using `groupadd`.*
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```
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<<base.alpinepre>>=
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RUN apk add --no-cache shadow
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@
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```
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```
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<<base.setupuser>>=
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RUN groupadd -g ${baseGID} ${baseUSER} && \
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useradd -c 'work user' -m -u ${baseUID} \
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-g ${baseGID} -d ${baseDIR} ${baseUSER} && \
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chown -R ${baseUID}:${baseGID} ${baseDIR}
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@
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```
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### Add repos and update software.
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First, we'll add any additional repo. If you have additional repos you want to
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enable, add them here.
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```
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<<base.enablerepos>>=
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# nothing to do here, carry on!
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@
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```
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### Addtional root changes
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We are still root at this point, this is where we add software, make
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additional changes, etc.
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```
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<<base.addsoftware>>=
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RUN apk update && apk upgrade --no-cache && \
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apk add --no-cache ed tcl joe
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@
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```
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The different sections are setup based on how often they may be changed.
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The more likely some will change, the further down they should be to help
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minimize the layers that need to be rebuilt.
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### Make sure we the user, volume, and workdir setup
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```
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<<base.end>>=
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USER ${baseUSER}
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VOLUME ${baseDIR}
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WORKDIR ${baseDIR}
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# you can add entry point, etc. here.
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@
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```
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### Pulling it all together
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```
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<<alpine.dockerfile>>=
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<<base.image>>
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<<base.userargs>>
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<<base.alpinepre>>
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<<base.setupuser>>
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<<base.enablerepos>>
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<<base.addsoftware>>
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<<base.end>>
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@
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```
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## build and test
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`docker build -t mek:alpine -f alpine.dockerfile .`
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`docker run --rm -it mek:alpine /bin/sh`
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```
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