DTR is the Docker Enterprise's platform registry, used to store and manage images. It is deployed on top of defined UCP worker nodes. DTR will run as a multi-container application. This means that all containers will run together, associated with just one defined node. In the case of node failure, no other nodes will take its DTR containers. This is very important because we need to deploy multiple DTR deployments, on different nodes.

DTR uses RethinkDB as a database to store and sync data between registry nodes. To provide high availability to DTR, we need to deploy an odd number of replicas. We will use three replicas, so we need to deploy DTR workloads on three worker nodes. Synchronization will be done using overlay networking. DTR installation will create a dtr-ol overlay network and this will be used internally for replica synchronization.

Each replica will deploy the following processes: