moby--moby/docs/sources/userguide/dockerrepos.md

page_title: Working with Docker Hub page_description: Learning how to use Docker Hub to manage images and work flow page_keywords: repo, Docker Hub, Docker Hub, registry, index, repositories, usage, pull image, push image, image, documentation

Working with Docker Hub

So far we've seen a lot about how to use Docker on the command line and your local host. We've seen how to pull down images that you can run your containers from and we've seen how to create your own images.

Now we're going to learn a bit more about Docker Hub and how you can use it to enhance your Docker work flows.

Docker Hub is the public registry that Docker Inc maintains. It contains a huge collection of images, over 15,000, that you can download and use to build your containers. It also provides authentication, structure (you can setup teams and organizations), work flow tools like webhooks and build triggers as well as privacy features like private repositories for storing images you don't want to publicly share.

Docker commands and Docker Hub

Docker acts as a client for these services via the docker search, pull, login and push commands.

Searching for images

As we've already seen we can search the Docker Hub registry via it's search interface or using the command line interface. Searching can find images by name, user name or description:

$ sudo docker search centos
NAME           DESCRIPTION                                     STARS     OFFICIAL   TRUSTED
centos         Official CentOS 6 Image as of 12 April 2014     88
tianon/centos  CentOS 5 and 6, created using rinse instea...   21
...

There you can see two example results: centos and tianon/centos. The second result shows that it comes from the public repository of a user, tianon/, while the first result, centos, doesn't explicitly list a repository so it comes from the trusted top-level namespace. The / character separates a user's repository and the image name.

Once you have found the image you want, you can download it:

$ sudo docker pull centos
Pulling repository centos
0b443ba03958: Download complete
539c0211cd76: Download complete
511136ea3c5a: Download complete
7064731afe90: Download complete

The image is now available to run a container from.

Contributing to Docker Hub

Anyone can pull public images from the Docker Hub registry, but if you would like to share your own images, then you must register a user first as we saw in the first section of the Docker User Guide.

To refresh your memory, you can create your user name and login to Docker Hub, or by running:

$ sudo docker login

This will prompt you for a user name, which will become a public namespace for your public repositories, for example:

training/webapp

Here training is the user name and webapp is a repository owned by that user.

If your user name is available then docker will also prompt you to enter a password and your e-mail address. It will then automatically log you in. Now you're ready to commit and push your own images!

Note: Your authentication credentials will be stored in the .dockercfg authentication file in your home directory.

Pushing a repository to Docker Hub

In order to push an repository to its registry you need to have named an image, or committed your container to a named image as we saw here.

Now you can push this repository to the registry designated by its name or tag.

$ sudo docker push yourname/newimage

The image will then be uploaded and available for use.

Features of Docker Hub

Now let's look at some of the features of Docker Hub. You can find more information here.

• Private repositories
• Organizations and teams
• Automated Builds
• Webhooks

Private Repositories

Sometimes you have images you don't want to make public and share with everyone. So Docker Hub allows you to have private repositories. You can sign up for a plan here.

Organizations and teams

One of the useful aspects of private repositories is that you can share them only with members of your organization or team. Docker Hub lets you create organizations where you can collaborate with your colleagues and manage private repositories. You can create and manage an organization here.

Automated Builds

Automated Builds automate the building and updating of images from GitHub or BitBucket, directly on Docker Hub. It works by adding a commit hook to your selected GitHub or BitBucket repository, triggering a build and update when you push a commit.

To setup an Automated Build

1. Create a Docker Hub account and login.
2. Link your GitHub or BitBucket account through the Link Accounts menu.
3. Configure an Automated Build.
4. Pick a GitHub or BitBucket project that has a Dockerfile that you want to build.
5. Pick the branch you want to build (the default is the master branch).
6. Give the Automated Build a name.
7. Assign an optional Docker tag to the Build.
8. Specify where the Dockerfile is located. The default is /.

Once the Automated Build is configured it will automatically trigger a build, and in a few minutes, if there are no errors, you will see your new Automated Build on the Docker Hub Registry. It will stay in sync with your GitHub and BitBucket repository until you deactivate the Automated Build.

If you want to see the status of your Automated Builds you can go to your Automated Builds page on the Docker Hub, and it will show you the status of your builds, and the build history.

Once you've created an Automated Build you can deactivate or delete it. You cannot however push to an Automated Build with the docker push command. You can only manage it by committing code to your GitHub or BitBucket repository.

You can create multiple Automated Builds per repository and configure them to point to specific Dockerfile's or Git branches.

Build Triggers

Automated Builds can also be triggered via a URL on Docker Hub. This allows you to rebuild an Automated build image on demand.

Webhooks

Webhooks are attached to your repositories and allow you to trigger an event when an image or updated image is pushed to the repository. With a webhook you can specify a target URL and a JSON payload will be delivered when the image is pushed.

Next steps

Go and use Docker!