Azure Red Hat OpenShift can utilize any server implementing the container image registry API as a source of images, including the Docker Hub, private registries run by third parties, and the integrated Azure Red Hat OpenShift registry.
Azure Red Hat OpenShift provides an integrated container image registry called OpenShift Container Registry (OCR) that adds the ability to automatically provision new image repositories on demand. This provides users with a built-in location for their application builds to push the resulting images.
Whenever a new image is pushed to OCR, the registry notifies Azure Red Hat OpenShift about the new image, passing along all the information about it, such as the namespace, name, and image metadata. Different pieces of Azure Red Hat OpenShift react to new images, creating new builds and deployments.
Azure Red Hat OpenShift can create containers using images from third party registries,
but it is unlikely that these registries offer the same image notification
support as the integrated Azure Red Hat OpenShift registry. In this situation
Azure Red Hat OpenShift will fetch tags from the remote registry upon imagestream
creation. Refreshing the fetched tags is as simple as running
<stream>. When new images are detected, the previously-described build and
deployment reactions occur.
Azure Red Hat OpenShift can communicate with registries to access private image repositories using credentials supplied by the user. This allows Azure Red Hat OpenShift to push and pull images to and from private repositories. The Authentication topic has more information.
If you need an enterprise-quality container image registry, Red Hat Quay is available both as a hosted service and as software you can install in your own data center or cloud environment. Advanced registry features in Red Hat Quay include geo-replication, image scanning, and the ability to roll back images.