This image builds an Alpine Linux rootfs, and by default outputs it as a tarball to stdout.

The mkrootfs script may also be used by itself to build a rootfs, which may be useful for e.g. a chroot. Note that mkrootfs depends on APK, so typically it will only be usable on an Alpine system. It should be possible to download and extract apk-tools-static and alpine-keys from the Alpine repos manually, but this is not supported.

default.md describes the image generated by the default options to mkrootfs.

The builder script takes the following options:

• -d dest: Sets the build destination. Defaults to mnt. This is unlikely to be useful when using the builder image. A volume mounted to the destination directory will collect the resulting rootfs, but this use is unsupported.
• -m mirror: Sets the base mirror URL. Defaults to the Glider Labs CDN proxy at http://dl-cdn.alpinelinux.org/alpine.
• -r release: Sets the release tag. Defaults to edge. A useful alternative might be latest-stable or v3.3.
• -p packages: Comma-separated packages list to be passed into apk add. Default is alpine-baselayout,alpine-keys,apk-tools,musl-utils, which is an unholy abomination providing a functional container with no init. A sane alternative might be alpine-base.
• -t timezone: Sets the timezone. If not provided, no timezone will be set, which is probably fine.
• -S: Suppress output of the rootfs tarball to stdout. This is most likely to be useful when running mkrootfs as a standalone script.