===== Overview =====

Using ''buildah'' on Fedora 30.

Links:

  * [[https://buildah.io/|buildah.io]]
  * [[https://opensource.com/article/18/6/getting-started-buildah|Getting started with Buildah]]
  * [[https://www.zdnet.com/article/buildah-1-0-linux-container-construction-made-easy/|​Buildah 1.0: Linux Container construction made easy]]
  * [[https://www.softwarefactory-project.io/software-factory-container-with-buildah-and-podman.html|Software Factory Container With Buildah And Podman]]
  * [[https://opensource.com/article/18/5/containers-buildah|Creating small containers with Buildah]]

===== Basics =====

''buildah'' sits on top of:

  * OCI containers/image project (copy, push, pull, inspect images)
  * OCI containers/storage project (store FS layers, images and containers)

''buildah'' can build images from any of:

  * existing images
  * scratch
  * Dockerfiles

Available commands:

<code>
  add                    Add content to the container
  build-using-dockerfile Build an image using instructions in a Dockerfile
  commit                 Create an image from a working container
  config                 Update image configuration settings
  containers             List working containers and their base images
  copy                   Copy content into the container
  from                   Create a working container based on an image
  help                   Help about any command
  images                 List images in local storage
  info                   Display Buildah system information
  inspect                Inspect the configuration of a container or image
  mount                  Mount a working container's root filesystem
  pull                   Pull an image from the specified location
  push                   Push an image to a specified destination
  rename                 Rename a container
  rm                     Remove one or more working containers
  rmi                    Remove one or more images from local storage
  run                    Run a command inside of the container
  tag                    Add an additional name to a local image
  umount                 Unmount the root file system of the specified working containers
  unshare                Run a command in a modified user namespace
  version                Display the Buildah version information
</code>

===== Build container from existing image =====

Delete all existing containers and check:

<code>
$ buildah rm --all
$ buildah containers
CONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME
$
</code>

Build from Fedora image and verify:

<code>
$ fc=$(buildah from fedora)
$ echo ${fc}
fedora-working-container
$
</code>

Run:

<code>
$ buildah run $fc bash
#
</code>

===== Running command in container =====

<code>
$ buildah run ${fc} cat /etc/os-release
</code>
===== Building containers from scratch =====

<code>
$ sc=$(buildah from scratch)
$ buildah containers
CONTAINER ID  BUILDER  IMAGE ID     IMAGE NAME                       CONTAINER NAME
6935a1961a34     *     d09302f77cfc docker.io/library/fedora:latest  fedora-working-container
4dd92fc19b8a     *                  scratch                          working-container
$
</code>