OpenShift Hands-On Lab - Building a Custom Image Using Podman

📝Introduction

In this lab, we will create a Dockerfile to start a web server using a custom configuration file copied from the host system, and this web server will listen on a non-standard port.

These are the objectives of this lab:

Set Up a New Build Directory
Complete the Dockerfile
Build and Test the New Image

📌Note1: When copying and pasting code into Vim from the lab guide, first enter :set paste (and then i to enter insert mode) to avoid adding unnecessary spaces and hashes. To save and quit the file, press Escape followed by :wq. To exit the file without saving, press Escape followed by :q!.

📝Log in to the AWS Management Console

Using your credentials, make sure you're using the right Region. In my case, I am using AWS as my cloud provider and chose us-east-1. However, for this hands-on lab, you can select any cloud provider to create your Linux server VMs (I am using a Red Hat Enterprise Linux 8.7 distro) and Podman 3.0.1 (Link to how to install Podman)

📌Note: You must create the AWS Access Key and AWS Secret Access Key and configure the AWS CLI in the terminal to use it.

You can use link1 and link2 for it.

📝Set Up a New Build Directory

Create a new build directory:
```
 mkdir demo_website_build
```

Create a customized index.html file and add it to the demo_website_build directory:

 cd demo_website_build/

 vi index.html

 <!DOCTYPE html>
 <html>
         <head>
                   <title>Custom Nginx Demo Website</title>
         </head>
         <body>
                   <h1>Hello, World!</h1>
                     <p>This is a demo website served by custom nginx.</p>
         </body>
 </html>

List the file:
```
 ls
```

📝Create the Dockerfile

Edit the Dockerfile:
```
 vim Dockerfile
```

Start the image with docker.io/nginx:latest:

 # Use the official NGINX base image
 FROM docker.io/nginx:latest

Set yourself as the maintainer:

 # Set youself as the Maintaner of this image
 MAINTAINER <NAME>

Add a description to the image next to LABEL description=:

 #Provide a brief ddescription of the image
 LABEL description="Demo test website"

Set a variable named PORT to a value of 80.

 # Set environment variables
 ENV PORT=80

Use the new variable to expose the port:
```
 # Expose port 80
 EXPOSE $PORT
```

Set the workdir to /usr/share/nginx/html:

 # Set the working directory
 WORKDIR /usr/share/nginx/html

Copy the HTML file to WORKDIR

 # Copy the HTML files to the working directory
 COPY index.html .

Set the container to start nginx with options -g and daemon off as overwritable options:

 # Define the entry point for the container
 ENTRYPOINT ["nginx"]
 # Set default command
 CMD ["-g", "daemon off;"]

Save and quit (remember to first press Escape):
```
:wq!
```

Build and Test the New Image

Build the new container image. This may take a few minutes:
```
 podman build -t demo-website:v1 .
```
Clear your screen:
```
 clear
```
Verify the image is there:
```
 podman images
```

Run the container:

 podman run -d --name=demo-website -p 8080:80 demo-website:v1

Verify the container started:
```
 podman ps
```
clear your screen.
Connect to the container:
```
 podman exec -it demo-website bash
```
Run a curl command to check if the website is working properly in the container:
```
 curl http://localhost
```
Exit out of the container:
```
 exit
```
Verify the website is available on port 8080 of the system using a web browser; copy your public IP address into a browser and add :8080 at the end.

📌Note - At the end of each hands-on Lab, always clean up all previous resources created to avoid being charged if you used a Cloud Provider to provision them.

Congratulations — you have completed this hands-on lab covering the basics of creating a Dockerfile to start a web server using a custom configuration file copied from the host system, and this web server will listen on a non-standard port using Podman.

Thank you for reading. I hope you understood and learned something helpful from my blog.

Please follow me on CloudDevOpsToLearn and LinkedIn, franciscojblsouza