Image tags and versioning in Docker - Mini Project: Build & Apply

Image tags and versioning

📖 Scenario: You work in a team that builds Docker images for a web application. To keep track of different versions, you use image tags. This helps you and your team know exactly which version of the app is running in different environments.

🎯 Goal: You will create a Docker image with a specific tag, then add a version tag, and finally list the images to see the tags clearly.

📋 What You'll Learn

Create a Dockerfile with a simple base image

Build a Docker image with the tag myapp:latest

Add a version tag myapp:v1.0 to the same image

List Docker images to verify both tags exist

💡 Why This Matters

🌍 Real World

Tagging Docker images helps teams deploy specific versions of applications reliably in development, testing, and production.

💼 Career

Understanding image tags and versioning is essential for DevOps roles managing containerized applications and continuous deployment pipelines.

1

Create a Dockerfile with a base image

Create a file named Dockerfile with the exact content: FROM alpine:latest

Docker

# Create a Dockerfile with the line: FROM alpine:latest

Need a hint?

This Dockerfile uses the Alpine Linux base image, which is very small and simple.

2

Build the Docker image with tag myapp:latest

Run the Docker build command to create an image tagged myapp:latest using the current directory as context.

Docker

# Run: docker build -t myapp:latest .

Need a hint?

Use docker build -t myapp:latest . to build the image.

3

Add a version tag myapp:v1.0 to the image

Use the Docker tag command to add the tag myapp:v1.0 to the existing image myapp:latest.

Docker

# Run: docker tag myapp:latest myapp:v1.0

Need a hint?

Use docker tag myapp:latest myapp:v1.0 to add the version tag.

4

List Docker images to verify tags

Run the Docker images command and filter the output to show only images named myapp.

Docker

# Run: docker images myapp

Need a hint?

Use docker images myapp to see all tags for the myapp image.