If you are a docker, you would know about the docker registry that’s a fully integrated distribution and storage system. It is organized into docker repositories where different versions of the images are saved. Sure, you have built the image, but how are you going to use the images on other platforms? How will you share the images with someone else or to another device where it can run? Well, just opt for the registries, and that’s all we are going to talk about in this article!

Docker Registry – What Is It?

The docker registry is a system for storing and distributing Docker images. It generally works as a target for docker pull and pushes commands. Before moving forward, there are some basic terminologies to learn about, such as;

• Image – this is a template for docker containers which has the associated layer series and a manifest 
• Layer – this is a representation of filesystem differences. These layers are integrated together to create one image that forms the filesystem’s base 
• Registry – this is the storage and delivery system for docker images. It can be represented as the collection of repositories 
• Repository – this is a collection of different versions of the docker image. The term is similar to git repository 
• Tag – it is simply a named version of the images, which allows the users to identify the images. The images can be tagged as you want, and it’s suggested to use the readable and meaningful name for identification later on 

Why Must You Use Docker Registry?

Well, sit back and imagine the workflow where a commit is pushed to trigger a build on the CI provider, which has the capacity to push a new image into the docker registry. The registry will be able to fire off the webhook, and deployment will be triggered. This is a suitable system because it eliminates the need for manual operations. The docker registry provides an automated workflow, hence the convenience. 

We have illustrated an example, and it shows that you will probably want a private registry for the storage of images. On the other hand, the public registry is suitable for open-source images and publicly available images. In case you have private images or sensitive snaps, it’s better to opt for the private registry. Also, there are hosted and self-hosted registries to choose from, so let’s see about them!

Hosted Docker Registries 

The hosted docker registries are the ones when you have to host the private registries or opt for third-party hosted registries. There are various hosted docker registries available, such as Quay.io, Docker Hub, AWS EC2 container registry, and Google Container registry.

Self-Hosted Docker Registries 

Truth be told, hosted docker registries are convenient to use since you hardly have to manage everything on your own. On the contrary, self-hosted docker registries provide control over where and how the images are stored. Also, these self-hosted registries offer flexibility in the distribution of images.