85 lines
2.6 KiB
ReStructuredText
85 lines
2.6 KiB
ReStructuredText
************************************
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Building and Using a Container Image
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************************************
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Building a container image based on CoreOS is really easy. You have to set
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the machine to either of the following value in the `local.conf` file:
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- container-x64
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- container-arm64
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- container-arm32
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.. hint::
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The machine can also be overwriting from the shell using
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`MACHINE=<machine> bitbake`
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Then you can generate any image by running:
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.. code-block:: sh
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$ bitbake <image>
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As an example, you can build the `coreos-image-minimal` as an OCI container
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for AMD64 machine with the following command:
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.. code-block:: sh
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$ MACHINE=container-x64 bitbake core-image-minimal
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This will generate a container tarball in the tar.gz format.
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If you are using `podman`, you can import the container with:
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.. code-block:: sh
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$ cd $BUILDDIR/tmp/deploy/images/container-x64
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$ podman import coreos-image-container-container-x64.tar.bz2
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Getting image source signatures
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Copying blob 46c0b1c53d42 [--------------------------------------] 0.0b / 0.0b
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Copying config 051856498a done
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Writing manifest to image destination
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Storing signatures
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051856498a59e0ae6349492539efaf915a33dd73e7a54ce9683b0414d1481fae
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Then you can use start any program included in the image with:
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.. code-block:: sh
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$ podman run <PODMAN_ARGS> <IMAGE_ID> <COMMAND> <COMMAND_ARGS>
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To run an interactive shell, you can use:
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.. code-block:: sh
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$ podman run -i <IMAGE_ID> ash --i
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/ #
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The `<IMAGE_ID>` should be copied from the output of `podman import`. In this
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exemple, it was
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`051856498a59e0ae6349492539efaf915a33dd73e7a54ce9683b0414d1481fae`.
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You are now inside the container, try the following command:
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.. code-block:: sh
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/ # cat /etc/os-release
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ID=belden-coreos
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NAME="Belden CoreOS"
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VERSION="0.0.1-feat/oci-image+75cf54e4b54b713d8ebeafddd122aeb615715ef9 (kirkstone)"
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VERSION_ID=0.0.1-feat/oci-image-75cf54e4b54b713d8ebeafddd122aeb615715ef9
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PRETTY_NAME="Belden CoreOS 0.0.1-feat/oci-image+75cf54e4b54b713d8ebeafddd122aeb615715ef9 (kirkstone)"
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DISTRO_CODENAME="kirkstone"
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.. note::
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Image generated using any container machines doesn't include the Linux
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kernel neither many system componant that are usually not used on a container
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like SystemD or udev. This is done inside the machine configuration by
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settings all the `VIRTUAL_RUNTIME_<component>` to an empty string.
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Any of these system component can be added to the image if needed, by adding
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them by their real name (instead of using any `VIRTUAL_RUNTIME_` variables)
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in the `IMAGE_INSTALL` variables.
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