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Docker Registry vs. Docker Repository

We used Docker Compose in Tip 55 to create an image using our existing ASP.NET WebAPI project and push it to Docker Cloud. I also covered deploying it to Azure using Web App for Containers. The bit of feedback that I feel that I didn't drive home was the difference between Docker Registry and Docker Repository. I wanted to cover that in this tip.

Docker Registry

Docker Registry is a service that stores your docker images, but it could be hosted by a third party and even private if you need so. A couple of examples are:

There are also other choices such as Google or AWS Container Registry.

Docker Repository

A Docker Repository is a collection of related images with same name, that have different tags. Tags are an alphanumeric identifier attached to images within a repository (e.g., 1.1 or latest).

So the command docker pull microsoft/aspnetcore:latest will download the image tagged latest within the microsoft/aspnetcore repository from the Docker Hub registry.

To wrap it up. Look at the image below. We have a Docker Repository named microsoft/aspnetcore that is stored in a Docker Registry using Docker Hub.

We could click on tags and pull the latest version with pull microsoft/aspnetcore:latest or version 1.1 with pull microsoft/aspnetcore:1.1