6f607df516
The way the documentation describes the zypper call to add a repository was wrong in several places.
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Build a Docker Container Image
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==============================
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.. sidebar:: Abstract
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This page explains how to build a Docker base image. It contains
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* basic configuration explanation
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* how to build a Docker image
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* how to run it with the Docker daemon
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KIWI is capable of building native Docker images, from scratch and derived
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ones. KIWI Docker images are considered to be native since the KIWI
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tarball image is ready to be loaded to a Docker daemon, including common
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container configurations.
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The Docker configuration metadata is provided to KIWI as part of the
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:ref:`XML description file <description_components>` using the
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``<containerconfig>`` tag. The following configuration metadata can be
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specified:
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`containerconfig` attributes:
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* ``name``: Specifies the repository name of the Docker
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image.
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* ``tag``: Sets the tag of the Docker image.
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* ``maintainer``: Specifies the author field of
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the container.
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* ``user``: Sets the user name or user id (UID) to be used when
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running `entrypoint` and
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`subcommand`. Equivalent of the `USER` directive of a Docker file.
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* ``workingdir``: Sets the working directory to be used when running `cmd` and
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`entrypoint`. Equivalent of the `WORKDIR` directive of a Docker file.
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`containerconfig` child tags:
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* ``subcommand``: Provides the default execution parameters of the
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container. Equivalent of the `CMD` directive of a Docker file.
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* ``labels``: Adds custom metadata to an image using key-value pairs.
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Equivalent to one or more `LABEL` directives of a Docker file.
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* ``expose``: Informs at which ports is the container listening at runtime.
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Equivalent to one or more `EXPOSE` directives of a Docker file.
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* ``environment``: Sets an environment values using key-value pairs.
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Equivalent to one or more the `env` directives of a Docker file.
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* ``entrypoint``: Sets the command that the container will run, it can
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include parameters. Equivalent of the `ENTRYPOINT` directive of a Docker
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file.
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* ``volumes``: Create mountpoints with the given name and mark it to hold
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external volumes from the host or from other containers. Equivalent to
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one or more `VOLUME` directives of a Docker file.
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Other Docker file directives such as ``RUN``, ``COPY`` or ``ADD``, can be
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mapped to KIWI by using the :ref:`config.sh <description_components>`
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script file to run bash commands or the
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:ref:`overlay tree <description_components>` to include extra files.
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The following example shows how to build a Docker base image based on
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openSUSE Leap:
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1. Make sure you have checked out the example image descriptions,
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see :ref:`example-descriptions`.
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#. Include the ``Virtualization/containers`` repository to your list:
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.. code:: bash
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$ zypper addrepo http://download.opensuse.org/repositories/Virtualization:/containers/<DIST> container-tools
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where the placeholder `<DIST>` is the preferred distribution.
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#. Install :command:`umoci` and :command:`skopeo` tools
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.. code:: bash
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$ zypper in umoci skopeo
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#. Build the image with KIWI:
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.. code:: bash
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$ sudo kiwi-ng --type docker system build \
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--description kiwi-descriptions/suse/x86_64/suse-tumbleweed-docker \
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--target-dir /tmp/myimage
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#. Test the Docker image.
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First load the new image
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.. code:: bash
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$ docker load -i openSUSE-Tumbleweed-container-image.x86_64-1.0.4.docker.tar.xz
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then run the loaded image:
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.. code:: bash
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$ docker run -it opensuse:42.2 /bin/bash
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