Setting Up Private Container Registries

1. Introduction

In this tutorial, we will guide you on how to set up a private container registry. A container registry is a place where you can store and distribute Docker images. Having a private registry ensures that your Docker images are securely stored and distributed within your organization.

Upon completing this tutorial, you will be able to:

• Understand what a private container registry is
• Set up your own private registry
• Push and pull Docker images from your private registry

Prerequisites:
- Basic knowledge of Docker
- Docker installed on your machine

2. Step-by-Step Guide

Concepts

A private Docker registry allows you to store and retrieve your Docker images. This is particularly useful when you want to distribute Docker images within your organization in a secure manner.

Setting Up Your Private Registry

The Docker Registry is a server-side application that lets you store and distribute Docker images. You can set up your own private registry using the Docker Registry open-source project.

1. Run the Registry as a Container:
   To set up a private registry, you can run the Docker Registry as a container on your Docker host. Here's a simple command to do that:

$ docker run -d -p 5000:5000 --name registry registry:2

In this command, -d tells Docker to run the container in the background, -p specifies the port number, --name names the container, and registry:2 is the image we want to use.

1. Push an Image to Your Registry:
   Now that you have a private registry, you can push an image to it.

First, tag an image with the registry's location on your Docker host. Here's an example:

$ docker tag ubuntu:16.04 localhost:5000/my-ubuntu

In this command, ubuntu:16.04 is the image we want to tag, and localhost:5000/my-ubuntu is the new tag.

Next, push the image to your private registry:

$ docker push localhost:5000/my-ubuntu

1. Pull an Image from Your Registry:
   To pull an image from your private registry, you can use the docker pull command:

$ docker pull localhost:5000/my-ubuntu

3. Code Examples

Here's a complete example of setting up a private registry, pushing an image, and pulling that image:

1. Run the registry:

# Run the Docker Registry in the background
$ docker run -d -p 5000:5000 --name registry registry:2

1. Push an image:

# Tag the image
$ docker tag ubuntu:16.04 localhost:5000/my-ubuntu

# Push the image
$ docker push localhost:5000/my-ubuntu

1. Pull the image:

# Pull the image
$ docker pull localhost:5000/my-ubuntu

4. Summary

In this tutorial, we have covered how to set up a private Docker registry, and how to push and pull images from that registry.

Next steps would be to explore managing your Docker images in your registry and setting up authentication for your private registry.

5. Practice Exercises

1. Exercise 1: Set up a private Docker registry and push a Docker image of your choice.

Solution: Follow the steps in the tutorial. Use any Docker image you like.

1. Exercise 2: Pull the image you pushed in the first exercise from the private registry.

Solution: Use the docker pull command to pull the image from your private registry.

1. Exercise 3: Try deleting your Docker image from your local machine and pulling it from your private registry.

Solution: Use the docker rmi command to remove the image, and then pull it from your private registry.

Remember, practice is key to mastering any skill. Keep experimenting with different Docker images and managing them in your private registry. Happy Dockerizing!