Building images with docker build - Mini Project: Build & Apply

Building images with docker build

📖 Scenario: You are working as a DevOps engineer. Your team needs a Docker image for a simple web application. You will create a Dockerfile, set a base image, add a configuration, build the image, and then check the image is created.

🎯 Goal: Build a Docker image step-by-step using the docker build command and a Dockerfile. You will create the Dockerfile, add a base image, add a label, build the image with a tag, and finally list the images to confirm the build.

📋 What You'll Learn

Create a Dockerfile with the exact name Dockerfile

Use the base image alpine:3.18

Add a label maintainer="[e-mail]"

Build the Docker image with the tag mywebapp:1.0

List Docker images to confirm the new image exists

💡 Why This Matters

🌍 Real World

Building Docker images is a key step in packaging applications for deployment in containers. This project simulates creating a basic image for a web app.

💼 Career

DevOps engineers and developers use Docker images to create consistent environments. Knowing how to build and tag images is essential for container workflows.

1

Create a Dockerfile with a base image

Create a file named Dockerfile and write the line FROM alpine:3.18 to set the base image.

Docker

# Create a Dockerfile with the line 'FROM alpine:3.18'
# Your code here

Need a hint?

The first line in a Dockerfile usually starts with FROM followed by the base image name and tag.

2

Add a maintainer label to the Dockerfile

Add the line LABEL maintainer="[e-mail]" below the FROM alpine:3.18 line in the Dockerfile.

Docker

FROM alpine:3.18
# Add a LABEL line with maintainer="[e-mail]" below
# Your code here

Need a hint?

The LABEL instruction adds metadata to the image. Use the exact key and value as shown.

3

Build the Docker image with a tag

Run the command docker build -t mywebapp:1.0 . in the terminal to build the Docker image using the current directory's Dockerfile and tag it as mywebapp:1.0.

Docker

FROM alpine:3.18
LABEL maintainer="[e-mail]"
# Run the docker build command below
# Your code here

Need a hint?

The docker build command builds an image from a Dockerfile. Use -t to tag the image with a name and version.

4

List Docker images to verify the build

Run the command docker images mywebapp:1.0 to list the Docker images and confirm that the image mywebapp:1.0 exists.

Docker

docker build -t mywebapp:1.0 .
# Run the docker images command below
# Your code here

Need a hint?

The docker images command shows all images. Filtering by the image name and tag helps confirm your build.