Chapter 4. Creating system images by using the RHEL image builder CLI

1. Create a blueprint or export an existing blueprint definition to a plain text file.
2. Optional: Edit this file in a text editor.
3. Import the blueprint text file back into image builder.
4. Run a compose to build an image from the blueprint.
5. Export the image file to download it.

Procedure

1. Create a plain text file with the following contents:

   name = "<blueprint_name>"
   description = "<long_form_description>"
   version = "<0.0.1>"
   modules = []
   groups = []

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   Replace <blueprint_name> and <long_form_description> with a name and description for your blueprint.

   Replace <0.0.1> with a version number according to the Semantic Versioning scheme.

2. For every package that you want to be included in the blueprint, add the following lines to the file:

   [[packages]]
   name = "<package_name>"
   version = "<package_version>"

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   Replace <package_name> with the name of the package, such as httpd, gdb-doc, or coreutils.

   Optionally, replace <package_version> with the version to use. This field supports dnf version specifications:

   • For a specific version, use the exact version number such as 9.6.0.
   • For the latest available version, use the asterisk *
   • For the latest minor version, use formats such as 9.*.

3. Customize your blueprints to suit your needs. For example, disable Simultaneous Multi Threading (SMT), add the following lines to the blueprint file:

   [customizations.kernel]
   append = "nosmt=force"

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   For additional customizations available, see Supported image customizations.

   Note that [] and [[]] are different data structures expressed in TOML.

   • The [customizations.kernel] header represents a single table that is defined by a collection of keys and their corresponding value pairs, for example: append = "nosmt=force".
   • The [[packages]] header represents an array of tables. The first instance defines the array and its first table element, for example, name = "package-name" and version = "package-version", and each subsequent instance creates and defines a new table element in that array, in the order that you defined them.
4. Save the file, for example, as <blueprint_name>.toml and close the text editor.

Procedure

1. Optional: List the image formats you can create:

   # image-builder list

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2. Start the compose:

   # image-builder build <image_type> --blueprint <blueprint_name>

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   • Replace <blueprint_name> with the name of the blueprint, and <image_type> with the type of the image.
   • If you do not specify a distro, image-builder uses the same distribution and version as the host system.