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Chapter 7. Creating a boot ISO installer image with RHEL image builder

You can use RHEL 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.

RHEL image builder builds a manifest that creates a boot ISO that contains a root file system. To create the ISO image, select the image type image-installer. RHEL 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 includes a pre-configured system image that you can install directly to a bare metal server.

7.1. Creating a boot ISO installer image using the RHEL image builder CLI

You can create a customized boot ISO installer image by using the RHEL image builder command-line interface. As a result, image builder builds an .iso file that contains a .tar file, which you can install for the Operating system. The .iso file is set up to boot Anaconda and install the .tar file to set up the system. You can use the created ISO image file on a hard disk or to boot in a virtual machine, for example, in an HTTP Boot or a USB installation.

Warning

The Installer (.iso) image type does not accept partitions customization. If you try to manually configure the filesystem customization, it is not applied to any system built by the Installer image. Mounting an ISO image built with RHEL image builder file system customizations causes an error in the Kickstart, and the installation does not reboot automatically. For more information, see Automate a RHEL ISO installation generated by image builder and Automate a RHEL ISO installation generated by image builder.

Prerequisites

  • You have created a blueprint for the image and customized it with a user included and pushed it back into RHEL image builder. See Blueprint customizations.

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. Wait until the compose is finished. This might take several minutes.

  2. Check the status of the compose: 

    # composer-cli compose status

    A finished compose shows a status value of FINISHED.

  3. Identify the compose in the list by its UUID. 

    # composer-cli compose list

  4. After the compose is finished, download the created image file to the current directory: 

    # composer-cli compose image UUID

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

    RHEL image builder builds a .iso file that contains a .tar file. The .tar file is the image that will be installed for the Operating system. The . iso is set up to boot Anaconda and install the .tar file to set up the system.

Next steps

In the directory where you downloaded the image file.

  1. Locate the .iso image you downloaded.

  2. Mount the ISO. 

    $ mount -o ro path_to_ISO /mnt

    You can find the .tar file at the /mnt/liveimg.tar.gz directory.

  3. List the .tar file content: 

    $ tar ztvf /mnt/liveimg.tar.gz

Additional resources

7.2. Creating a boot ISO installer image by using RHEL image builder in the GUI

You can build a customized boot ISO installer image by using the RHEL image builder GUI. You can use the resulting ISO image file on a hard disk or boot it in a virtual machine. For example, in an HTTP Boot or a USB installation.

Warning

The Installer (.iso) image type does not accept partitions customization. If you try to manually configure the filesystem customization, it is not applied to any system built by the Installer image. Mounting an ISO image built with RHEL image builder file system customizations causes an error in the Kickstart, and the installation does not reboot automatically. For more information, see Automate a RHEL ISO installation generated by image builder and Automate a RHEL ISO installation generated by image builder.

Prerequisites

Procedure

  1. On the RHEL image builder dashboard, locate the blueprint that you want to use to build your image. Optionally, enter the blueprint name or a part of it into the search box at upper left, and click Enter.

  2. On the right side of the blueprint, click the corresponding Create Image button.

    The Create image dialog wizard opens.

  3. On the Create image dialog wizard:

    1. In the Image Type list, select "RHEL Installer (.iso)".
    2. Click Next.

    3. On the Review tab, click Create.

      RHEL image builder adds the compose of a RHEL ISO image to the queue.

      After the process is complete, you can see the image build complete status. RHEL image builder creates the ISO image.

Verification

After the image is successfully created, you can download it.

  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. 

    $ tar -xf content.tar

Additional resources

7.3. Installing a bootable ISO to a media and booting it

Install the bootable ISO image you created by using RHEL image builder to a bare metal system.

Prerequisites

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. Insert the flash drive into a USB 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.

Additional resources