Create a Customized Nginx Docker Image¶

Let's see how you can create your own Docker image based on your requirements. In this tutorial, we will create a customized version of the Nginx image that serves an HTML page we want.

Step 1: Create HTML File to Be Served by Nginx¶

By default, nginx serves the index.html file present in /usr/share/nginx/html directory. You can verify this by checking the content of /etc/nginx/conf.d/default.conf.

We'll replace the default index.html with our customized index.html file.

Let's create the customized index.html file as follows:

index.html

<!doctype html>
<html>
    <head>
        <title>Nginx</title>
    </head>
    <body>
        <h2>Hello from Nginx Container</h2>
    </body>
</html>

Step 2: Create Dockerfile¶

A Dockerfile is like a step-by-step instruction manual for creating a Docker image. It's a plain text file that contains a series of commands and settings that define how to construct a container image.

Create the Dockerfile as follows:

Dockerfile

FROM nginx:latest
COPY ./index.html /usr/share/nginx/html/index.html

What does this Dockerfile do?

It specifies the base image as the latest version of the official Nginx image.
It copies the local index.html file into the Nginx container to replace the default one.

Note

A "base image" is the initial image used as a starting point when creating a custom Docker image.

Here's what your folder structure should look like:

|-- my-folder
│   |-- index.html
│   |-- Dockerfile

Step 3: Build the Image¶

Now that we have the Dockerfile and custom index.html file ready, we can use the docker build command to create the Docker image as follows:

# Command template
docker build -t <image-name>:<image-tag> <path-to-Dockerfile>

# Actual command
docker build -t my-nginx-image:v1 .

What does the above command do?

It creates an image from the Dockerfile we provide
It assigns the image a tag of v1

Step 4: List Images¶

List Docker images to verify if the image we built is present:

docker images

You should see the newly built image in the list.

Step 5: Run Container From the Image¶

Run a container from the newly created image as follows:

docker run -d --name my-nginx-container -p 81:80 my-nginx-image:v1

What does the above command do?

It runs a container named my-nginx-container in detached mode, using the image my-nginx-image:v1
Additionally, it exposes port 80 of the container to port 81 on the host

Step 6: Access the Nginx Application¶

Access the application from inside the container:
```
# Start a shell session inside the container
docker exec -it my-nginx-container bash

# Access the localhost endpoint
curl localhost
```
You'll notice that the custom Nginx page we provided is being served.

You can also see the custom HTML we provided file as follows:
```
cat /usr/share/nginx/html/index.html
```
Access the application from host machine:

Since we've exposed our application to the host through port mapping, you can simply open any browser on your host and visit the following endpoint to access the application:
```
localhost:81
```
You'll see the custom nginx page we provided.

Step 7: View Container Logs¶

View the container logs as follows:

# Command template
docker logs -f <container-id/container-name>

# Actual command
docker logs -f my-nginx-container

In your browser, visit localhost:81 a few times, and you'll see the Nginx access log being streamed in the console.

Step 8: Clean Up¶

# Stop the container
docker stop my-nginx-container

# Delete the container
docker rm my-nginx-container

Note

A container needs to be stopped before it can be deleted. You can't delete a running container.