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Creating a private Docker registry

All Yours

Article from ADMIN 60/2020

By Chris Binnie

A private Docker registry gives you more control over images and protects your Docker Hub credentials.

During testing, a local Docker registry for your container images can be useful. Images stored locally within a mini-registry give you more control over them, with improvements in speed when pulling the images. Also, you might be working with an application that needs access to a registry for one reason or another, but you do not want to give the application your Docker Hub credentials.

In this article, I look at installing a private Docker registry on a local machine (Ubuntu LTS 18.04 with Linux Mint on top) for testing purposes.

On Your Marks

The documentation from Docker on private registries is really detailed, but every now and again a local setup has unusual issues. To begin, you need to make sure that the latest version of Docker Community Edition (Docker CE) is installed. I used the documentation online [1], which you can reference if you get stuck and need more help.

As the root user, run:

$ apt remove docker docker-engine docker.io containerd runc

This command removes all other package manager versions or manually installed versions of Docker, so you can ensure that you are definitely using the Docker CE version. The documentation offers some reassurance that any container-related files residing within the /var/lib/docker directory are not deleted during this process.

Next, install the package manager tools you will need (some or all of these packages might already be present), then add Docker's key (success is denoted by a simple OK ), and check the key's fingerprint:

$ apt install apt-transport-https ca-certificates curl gnupg-agent software-properties-common
$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
OK
$ apt-key fingerprint 0EBFCD88

Have a look at the second line of the final command's output (

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