Composer images are images that are generated by the composer-cli compose command.

The actual creation of a custom image occurs when you run the composer-cli compose command against a blueprint. Therefore, the image is called a composer image. A composer image is the final result of the image building process.

Aside from the definitions that are specified in the blueprint, a composer image also includes logs, metadata, and the processes that run to create the image.

Composer images can be produced in different output formats. For example: oci, qcow, and tar. For each type, the system automatically installs default packages. Also, the type has associated services that are enabled automatically when the image is deployed. For example, for a tar image, the system automatically includes the policycoreutils and selinux-policy-targetd packages. However, no extra services are enabled.

Customizations in the blueprint can specify other services that need to be enabled. However, these customizations can't override the required services for an image type that are automatically enabled when the image is deployed.

For more information about the different image types, see: Image Types and Output Formats.