Which specification defines the format of an image that can be stored in a registry?

Which specification defines the format of an image that can be stored in a registry?

• A. Image Specification
• B. Runtime Specification
• C. OCI Image Specification
• D. Distribution Specification

Answer: (C)

The format of an image stored in a registry is defined by the OCI Image Specification. This specification standardizes how an image is laid out: a config blob that describes the image, a set of layer blobs representing filesystem changes, and a manifest that ties the config and layers together. This common structure lets different tools and registries interoperate, so images built with one tool can be stored in and read by others. Other specs cover different aspects. The Runtime Specification defines how a container should be executed, not how an image is laid out. The Distribution Specification governs how registries push and pull artifacts, but not the internal format of the image itself. The term “Image Specification” is not the formal designation used for the image format in this context, whereas the OCI Image Specification is the official standard for image formats.

The format of an image stored in a registry is defined by the OCI Image Specification. This specification standardizes how an image is laid out: a config blob that describes the image, a set of layer blobs representing filesystem changes, and a manifest that ties the config and layers together. This common structure lets different tools and registries interoperate, so images built with one tool can be stored in and read by others.

Other specs cover different aspects. The Runtime Specification defines how a container should be executed, not how an image is laid out. The Distribution Specification governs how registries push and pull artifacts, but not the internal format of the image itself. The term “Image Specification” is not the formal designation used for the image format in this context, whereas the OCI Image Specification is the official standard for image formats.