Getting started with DockerHub

You can also use the publicly released official Docker image. I use a lot of these images, including for my experimental WordPress environment, KDE plasma applications, and more. Although we learned how to create your own Docker image last time, you don’t have to. There are thousands of images published on DockerHub for you to use. DockerHub is hard-coded into Docker as the default repository, so when you run the docker pull command on any image, it will be downloaded from DockerHub.

To get started please check out the previous articles in this series to continue. Then, once Docker is running on your system, you can open a terminal and run:

$ docker images

This command will display all docker images on the current system. Assuming you want to deploy Ubuntu on your local machine, you might:

$ docker pull ubuntu

If an Ubuntu image already exists on your system, this command will automatically update the system to the latest version. So if you want to update an existing image, just run the docker pull command and it's a piece of cake. It's just like apt-get update without all the mess and hassle.

You already know how to run an image:

$ docker run -it 
$ docker run -it ubuntu

The command prompt should change to the following:

root@1b3ec4621737<span class="pun">:/#
</span>

Now you can run any command and utility that comes with Ubuntu, it’s included and safe. You can run all the experiments and tests you want on Ubuntu. Once you've finished testing, you can destroy the image and download a new one. There is no system overhead in a virtual machine.

You can exit the container by running the exit command:

$ <span class="kwd">exit
</span>

Now assuming you want to install Nginx on your system, run the search command to find the required image:

$ docker search nginx

As you can see, there are many Nginx images on DockerHub. Why? Because anyone can publish an image, various images are optimized for different projects, so you can choose the right image. You just need to install the appropriate image for your needs.

Suppose you want to pull Bitnami’s Nginx image:

$ docker pull bitnami<span class="pun">/</span><span class="pln">nginx
</span>

Now running:

$ docker run <span class="pun">-</span><span class="pln">it bitnami</span><span class="pun">/</span><span class="pln">nginx
</span>

Before this, we learned how to create a Docker image that we can easily publish to DockerHub. First, you need to log in to DockerHub. If you don't have an account, please create one. Then, you can open the Terminal app and log in:

$ docker <span class="kwd">login</span> <span class="pun">--</span><span class="pln">username</span><span class="pun">=<span class="pln">USERNAME</span><span class="pun">>
</span></span>

Replace "" with your own Docker Hub username. This is arnieswap:

$ docker <span class="kwd">login</span> <span class="pun">--</span><span class="pln">username</span><span class="pun">=</span><span class="pln">arnieswap
</span>

Enter your password and you are logged in. Now run the docker images command to get the ID of the image you last created.

$ docker images

Now, assuming you want to push the image ng to DockerHub, first, we need to tag the image (learn more about tagging):

$ docker tag e7083fd898c7 arnieswap<span class="pun">/</span><span class="pln">my_repo</span><span class="pun">:</span><span class="pln">testing
</span>

Push the image now:

$ docker push arnieswap<span class="pun">/</span><span class="pln">my_repo
</span>

The push points to the docker.io/arnieswap/my_repo warehouse:

12628b20827e: Pushed
8600ee70176b: Mounted from library/ubuntu
2bbb3cec611d: Mounted from library/ubuntu
d2bb1fc88136: Mounted from library/ubuntu
a6a01ad8b53f: Mounted from library/ubuntu
833649a3e04c: Mounted from library/ubuntu
testing: digest: sha256:286cb866f34a2aa85c9fd810ac2cedd87699c02731db1b8ca1cfad16ef17c146 size: 1569

Oh yeah! Your image is being uploaded. Once completed, open DockerHub, log in to your account, and you should see your first Docker image. Now anyone can deploy your image. This is the easiest and fastest way to develop and release software. Whenever you update the image, users can simply run:

$ docker run arnieswap<span class="pun">/</span><span class="pln">my_repo
</span>

Now you know why people love Docker containers. It solves many of the problems faced by traditional workloads and allows you to develop, test, and deploy applications at any time. By following the steps in this series, you can try the following yourself.

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