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Chapter 6. Creating a boot ISO installer image with Image Builder

You can use Image Builder to create bootable ISO Installer images. These images consist of a .tar file that has a root file system. You can use the bootable ISO image to install the file system to a bare metal server.

Image Builder builds a manifest that creates a boot ISO that has the commit and a root file system. To create the ISO image, select the image type image-installer. Image Builder builds a .tar file with the following content:

  • a standard Anaconda installer ISO
  • an embedded RHEL system tar file
  • a default Kickstart file that installs the commit with minimal default requirements

The created installer ISO image embeds a pre-configured system image that you can install directly to a bare metal server.

6.1. Creating a boot ISO installer image with Image Builder in the command-line interface

This procedure shows how to build a custom boot ISO installer image using the Image Builder command-line interface.

Prerequisites

Procedure

  1. Create the ISO image:

    # composer-cli compose start BLUEPRINT-NAME image-installer
    • BLUEPRINT-NAME with name of the blueprint you created
    • image-installer is the image type

      The compose process starts in the background and the UUID of the compose is shown.

  2. Wait until the compose is finished. Note that this may take several minutes.

    To check the status of the compose:

    # composer-cli compose status

    A finished compose shows a status value of FINISHED. Identify the compose in the list by its UUID.

  3. After the compose is finished, download the resulting image file:

    # composer-cli compose image UUID

    Replace UUID with the UUID value shown in the previous steps.

    As a result, Image Builder builds a .tar file that contains the ISO Installer image.

Verification

  1. Navigate to the folder where you downloaded the image file.
  2. Locate the .tar image you downloaded.
  3. Extract the .tar content.

You can use the resulting ISO image file on a hard drive or to boot in a virtual machine, for example, in an HTTP Boot or a USB installation.

6.2. Creating a boot ISO installer image with Image Builder in the GUI

You can build a customized boot ISO installer image using Image Builder GUI.

Prerequisites

  • You created a blueprint for your image.

Procedure

  1. Open the Image Builder interface of the RHEL web console in a browser.
  2. Locate the blueprint that you want to build your image by entering its name or a part of it into the search box at top left, and click Enter.
  3. On the right side of the blueprint, click the Create Image button that belongs to the blueprint.

    The Create image dialog wizard opens.

  4. On the Create image dialog wizard, from the Image Type list:

    1. Select the "RHEL Installer (.iso)" image type.
    2. Click Create.

Image Builder adds the compose of a RHEL ISO image to the queue.

Note

The image build process take a few minutes to complete.

After the process is complete, you can see the Image build complete status. Image Builder creates the ISO image.

Verification

After the image is successfully created, you can download your image button.

  1. Click Download to save the "RHEL Installer (.iso)" image to your system.
  2. Navigate to the folder where you downloaded the "RHEL Installer (.iso)" image.
  3. Locate the .tar image you downloaded.
  4. Extract the "RHEL Installer (.iso)" image content.

You can use the resulting ISO image file on a hard disk drive or to boot in a virtual machine, for example, in an HTTP Boot or a USB installation.

6.3. Installing the ISO image to a bare metal system

Install the bootable ISO image you created by using Image Builder to a bare metal system.

Prerequisites

  • You created the bootable ISO image by using Image Builder.
  • You have downloaded the bootable ISO image.
  • You installed the dd tool.
  • You have a USB flash drive with enough capacity. The recommended minimum is 8 GB.

    Note

    The ISO size might vary depending on the configuration specified in the blueprint, and especially depends on the packages you have added to the blueprint.

Procedure

  1. Write the bootable ISO image directly to the USB drive using the dd tool. For example:

    dd if=installer.iso of=/dev/sdX

    Where installer.iso is the ISO image file name and /dev/sdX is your USB flash drive device path.

  2. Connect the USB flash drive to the port of the computer you want to boot.
  3. Boot the ISO image from the USB flash drive.

    When the installation environment starts, you might need to complete the installation manually, similarly to the default Red Hat Enterprise Linux installation.