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title: About disconnected installation mirroring
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# About disconnected installation mirroring {#installing-mirroring-disconnected-about}

As a cluster administrator, you can use a mirror registry to ensure that your clusters only use container images that satisfy your organizational controls on external content.

## Mirror registries for installing clusters in disconnected environments {#installing-mirroring-disconnected-con_installing-mirroring-disconnected-about}

You must mirror required container images into a disconnected environment before you can install and provision a cluster there. To mirror those container images, you must have a mirror registry.

Consider the following options for creating and using a mirror registry:

- If you already have a container image registry, such as Red Hat Quay, you can use it as your mirror registry. If you do not already have a registry, you must create one.
- After you establish your registry, you need mirroring tools. To mirror your OpenShift Container Platform image repository to the mirror registry in your disconnected environment, you can use the oc-mirror OpenShift CLI (`oc`) plugin. The oc-mirror plugin is a single tool that mirrors all required OpenShift Container Platform content and other images to your mirror registry. The oc-mirror plugin is the preferred method for mirroring.
- Alternately, you can use the `oc adm` command to mirror just release and catalog images for OpenShift Container Platform.