OpenShift Container Platform

Work with manifest lists

To precisely manage multi-architecture or variant images contained within a manifest list, use the --import-mode flag with oc import-image or oc tag CLI commands. This functionality allows you to import a single sub-manifest, or all manifests, of a manifest list, providing fine-grained control over your image stream content.

In some cases, users might want to use sub-manifests directly. When oc adm prune images is run, or the CronJob pruner runs, they cannot detect when a sub-manifest list is used. As a result, an administrator using oc adm prune images, or the CronJob pruner, might delete entire manifest lists, including sub-manifests.

To avoid this limitation, you can use the manifest list by tag or by digest instead.

Procedure

Create an image stream that includes multi-architecture images, and sets the import mode to PreserveOriginal, by entering the following command:

$ oc import-image <multiarch-image-stream-tag>  --from=<registry>/<project_name>/<image-name> \
--import-mode='PreserveOriginal' --reference-policy=local --confirm

Example output

---
Arch:           <none>
Manifests:      linux/amd64     sha256:6e325b86566fafd3c4683a05a219c30c421fbccbf8d87ab9d20d4ec1131c3451
                linux/arm64     sha256:d8fad562ffa75b96212c4a6dc81faf327d67714ed85475bf642729703a2b5bf6
                linux/ppc64le   sha256:7b7e25338e40d8bdeb1b28e37fef5e64f0afd412530b257f5b02b30851f416e1
---

Alternatively, enter the following command to import an image with the Legacy import mode, which discards manifest lists and imports a single sub-manifest:

$ oc import-image <multiarch-image-stream-tag>  --from=<registry>/<project_name>/<image-name> \
--import-mode='Legacy' --confirm

The --import-mode= default value is Legacy. Excluding this value, or failing to specify either Legacy or PreserveOriginal, imports a single sub-manifest. An invalid import mode returns the following error: error: valid ImportMode values are Legacy or PreserveOriginal.