Tagging images during build in Docker - Mini Project: Build & Apply

Tagging Docker Images During Build

📖 Scenario: You are working on a small web application that you want to package into a Docker image. To keep track of different versions, you need to tag the Docker image properly during the build process.

🎯 Goal: Build a Docker image from a simple Dockerfile and tag it with a specific version tag during the build.

📋 What You'll Learn

Create a Dockerfile with a base image and a simple command

Define a version tag variable

Build the Docker image using the version tag

Display the tagged image in the local Docker images list

💡 Why This Matters

🌍 Real World

Tagging Docker images helps teams manage different versions of their applications easily, especially when deploying to production or testing environments.

💼 Career

Knowing how to tag Docker images during build is a fundamental skill for DevOps engineers and developers working with containerized applications.

1

Create a simple Dockerfile

Create a file named Dockerfile with the following content exactly:
FROM alpine:latest
CMD ["echo", "Hello, Docker!"]

Docker

# Create a Dockerfile with FROM alpine:latest and CMD ["echo", "Hello, Docker!"]

Need a hint?

The Dockerfile must start with FROM alpine:latest and end with CMD ["echo", "Hello, Docker!"].

2

Define a version tag variable

Create a shell variable called VERSION and set it to v1.0 exactly.

Docker

# Define VERSION variable
# Your code here

Need a hint?

Use VERSION=v1.0 to define the version tag variable.

3

Build the Docker image with the version tag

Write the exact shell command to build the Docker image from the current directory using the tag myapp:${VERSION}.

Docker

VERSION=v1.0

# Build the Docker image with tag myapp:${VERSION}
# Your code here

Need a hint?

Use docker build -t myapp:${VERSION} . to build and tag the image.

4

Display the tagged Docker image

Write the exact shell command to list Docker images and filter the output to show only images with the name myapp.

Docker

VERSION=v1.0

docker build -t myapp:${VERSION} .

# List Docker images filtered by name myapp
# Your code here

Need a hint?

Use docker images myapp to see the tagged image.