// Module included in the following assemblies:
//
// * installing/disconnected_install/installing-mirroring-installation-images.adoc

:_mod-docs-content-type: CONCEPT
[id="mirror-registry-introduction_{context}"]
= Mirror registry for Red Hat OpenShift introduction

[role="_abstract"]
For disconnected deployments of {product-title}, a container registry is required to carry out the installation of the clusters. To run a production-grade registry service on such a cluster, you must create a separate registry deployment to install the first cluster. The _mirror registry for Red{nbsp}Hat OpenShift_ addresses this need and is included in every {product-title} subscription. It is available for download on the "OpenShift console Downloads" page.

The _mirror registry for Red{nbsp}Hat OpenShift_ allows users to install a small-scale version of {quay} and its required components by using the `mirror-registry` command-line interface (CLI) tool. The _mirror registry for Red{nbsp}Hat OpenShift_ is deployed automatically with pre-configured local storage and a local database. It also includes auto-generated user credentials and access permissions with a single set of inputs and no additional configuration choices to get started.

The _mirror registry for Red{nbsp}Hat OpenShift_ provides a pre-determined network configuration and reports deployed component credentials and access URLs upon success. A limited set of optional configuration inputs such as fully qualified domain name (FQDN) services, superuser name and password, and custom TLS certificates are also provided. This provides users with a container registry so that they can easily create an offline mirror of all {product-title} release content when running {product-title} in restricted network environments.

Use of the _mirror registry for Red{nbsp}Hat OpenShift_ is optional if another container registry is already available in the install environment.

[id="mirror-registry-limitations_{context}"]
== Mirror registry for Red Hat OpenShift limitations

The following limitations apply to the _mirror registry for Red{nbsp}Hat OpenShift_:

* The _mirror registry for Red{nbsp}Hat OpenShift_ is not a highly-available registry and only local file system storage is supported. It is not intended to replace {quay} or the internal image registry for {product-title}.

* The _mirror registry for Red{nbsp}Hat OpenShift_ is not intended to be a substitute for a production deployment of {quay}.

* The _mirror registry for Red{nbsp}Hat OpenShift_ is only supported for hosting images that are required to install a disconnected {product-title} cluster, such as Release images or Red{nbsp}Hat Operator images. It uses local storage on your {op-system-base-full} machine, and storage supported by {op-system-base} is supported by the _mirror registry for Red{nbsp}Hat OpenShift_.
+
[NOTE]
====
Because the _mirror registry for Red{nbsp}Hat OpenShift_ uses local storage, you should remain aware of the storage usage consumed when mirroring images and use {quay}'s garbage collection feature to mitigate potential issues. For more information about this feature, see "{quay} garbage collection".
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* Support for Red{nbsp}Hat product images that are pushed to the _mirror registry for Red{nbsp}Hat OpenShift_ for bootstrapping purposes are covered by valid subscriptions for each respective product. For a list of exceptions to further enable the bootstrap experience, see "Self-managed Red{nbsp}Hat OpenShift sizing and subscription guide".

* Content built by customers should not be hosted by the _mirror registry for Red{nbsp}Hat OpenShift_.

* Using the _mirror registry for Red{nbsp}Hat OpenShift_ with more than one cluster is discouraged because multiple clusters can create a single point of failure when updating your cluster fleet. Instead, use the _mirror registry for Red{nbsp}Hat OpenShift_ to install a cluster that can host a production-grade, highly-available registry such as {quay}, which can serve {product-title} content to other clusters.
