About Default Image Builder Repositories

Composed images use Image Builder repositories to download their required packages.

The Image Builder repository contains definitions for building images based on different major versions of Oracle Linux. You can therefore use Image Builder to build an image for a version of Oracle Linux that's different to the version running on the Image Builder host.

Note:

The image that Image Builder creates for a release of Oracle Linux includes all the latest packages for that release. You can't build an image for a specific update level.

Image Builder doesn't use the system repositories that are defined in /etc/yum.repos.d/ in a typical Oracle Linux installation. Instead, the repository definitions for Image Builder are automatically installed in /usr/share/osbuild-composer/repositories. In this directory, repository definitions are contained in files in JSON format, which is different from the *.repo files in /etc/yum.repos.d/.

Each file corresponds to the latest update of a major version of Oracle Linux. For example, the following extract is from the ol-8.json repository file for the latest Oracle Linux 8 release on the x86_64 platform.

{
    "x86_64": [
        {
            "name": "baseos",
            "baseurl": "https://yum$ociregion.$ocidomain/repo/OracleLinux/OL8/baseos/latest/x86_64",
            "check_gpg": false,
            "rhsm": false
        },
        {
            ...other repositories...
        }
    ]
}

The repository definitions in the JSON file correspond to information in the parallel *.repo file in the /etc/yum.repos.d directory. In the previous example, the JSON file is based on the /etc/yum.repos.d/oracle-linux-ol8.repo file.

You can override the default repositories in /usr/share/osbuild-composer/repositories by defining custom repositories in a different location.