3.4

3.4 Lab - The Docker Hub with Nano Editor

Introduction

In this hands-on lab, we will explore the functionalities of Docker Hub by pulling an image, customizing it, and pushing the customized image back to Docker Hub, using the Nano editor in a Linux environment. Docker Hub serves as a central repository for Docker images, offering an array of public and private repositories. This lab is designed to provide you with practical experience in managing Docker images and using Docker Hub for collaboration and sharing.

Objectives

Pull an image from Docker Hub.
Customize a Docker image using the Nano editor.
Tag and push the customized image to Docker Hub.

Lab Steps

Step 1: Set Up Your Environment

Ensure you are logged into a Linux environment with Docker installed and that you have internet access.
If not already installed, install the Nano editor with your package manager (e.g., sudo apt-get install nano on Ubuntu).

Step 2: Pull an Image from Docker Hub

Open a terminal.
Execute the command to pull the official Nginx image:
```
docker pull nginx:latest
```

Step 3: Customize the Image Using Nano

Create a directory for your Docker project and navigate into it:
```
mkdir nginx-custom
cd nginx-custom
```
Launch Nano to create a new Dockerfile:
```
nano Dockerfile
```
Enter the following content to use the Nginx image as a base and add a custom HTML file:
```
FROM nginx:latest
COPY custom-index.html /usr/share/nginx/html/index.html
```
Save your changes in Nano (CTRL+O, Enter) and exit (CTRL+X).
Create the custom HTML file:
```
nano custom-index.html
```

Add some HTML content, such as:

<html>
<head><title>Custom Nginx Page</title></head>
<body><h1>Hello, Docker Hub!</h1></body>
</html>

Save and exit Nano as previously described.

Step 4: Build, Tag, and Push the Image to Docker Hub

Build your custom Docker image:
```
docker build -t my_custom_nginx .
```
Log into Docker Hub from the command line (you'll be prompted for your Docker Hub username and password):
```
docker login
```

You should see the following confirmation:

WARNING! Your password will be stored unencrypted in /home/admin/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded

Tag your custom image with your Docker Hub username and repository name. Replace <your_username> with your actual username:
```
docker tag my_custom_nginx <your_username>/my_custom_nginx:latest
```

Push the tagged image to your Docker Hub repository:

docker push <your_username>/my_custom_nginx:latest

You should see the following confirmation:

The push refers to repository [docker.io/efrick9999/my_custom_nginx]
c3c7817ac517: Pushed 
f205d290cd76: Mounted from library/nginx 
2b28485849ea: Mounted from library/nginx 
9f21a390e3f6: Mounted from library/nginx 
06536efc503a: Mounted from library/nginx 
84e0c9ef07d7: Mounted from library/nginx 
83bdf27d9eaa: Mounted from library/nginx 
fb1bd2fc5282: Mounted from library/nginx 
latest: digest: sha256:9679f58a1ac09c8d45326c1a06a63789f76064ae38245befd45e5812fd57b9a0 size: 1985

Step 5: Login to Docker Hub

If you log into the Docker Hub website at https://hub.docker.com you should see your image you pushed under you repositories.

Summary

In this lab, you've successfully navigated through the process of pulling an image from Docker Hub, customizing it by creating and editing files with the Nano editor, and pushing your customized image back to Docker Hub. These skills are fundamental to managing Docker images and utilizing Docker Hub for sharing and collaboration purposes. You've learned how to employ a simple text editor like Nano to edit Dockerfiles and other necessary files in a Linux environment, providing you with the flexibility to customize your Docker images directly from the command line.