Image naming conventions (registry/image:tag) in Docker - Mini Project: Build & Apply

Image naming conventions (registry/image:tag)

📖 Scenario: You are working with Docker images and need to understand how to name them properly. Docker images use a naming format that helps you identify where the image is stored, what the image is, and which version it is.

🎯 Goal: Learn how to create and use Docker image names with the correct format: registry/image:tag. You will build a simple example of naming an image with a registry, image name, and tag.

📋 What You'll Learn

Create a variable with a Docker image name using the format registry/image:tag

Add a variable for the default registry

Extract the image name and tag from the full image name

Print the extracted image name and tag

💡 Why This Matters

🌍 Real World

Docker images are used to package applications and their environments. Knowing how to name and tag images helps you manage versions and sources clearly.

💼 Career

Understanding image naming conventions is essential for DevOps roles that involve container management, deployment pipelines, and working with container registries.

1

Create a Docker image name variable

Create a variable called full_image_name and set it to the string docker.io/library/ubuntu:22.04.

Docker

# Create a variable called full_image_name with the value 'docker.io/library/ubuntu:22.04'
# Your code here

Need a hint?

Remember to use quotes around the string value.

2

Add a default registry variable

Create a variable called default_registry and set it to the string docker.io.

Docker

full_image_name = "docker.io/library/ubuntu:22.04"
# Create a variable called default_registry with the value 'docker.io'
# Your code here

Need a hint?

This variable will help identify the registry part of the image name.

3

Extract image name and tag from full image name

Use the split method on full_image_name to create two variables: image_name for the part after the registry and before the colon, and tag for the part after the colon. For example, image_name should be library/ubuntu and tag should be 22.04.

Docker

full_image_name = "docker.io/library/ubuntu:22.04"
default_registry = "docker.io"
# Extract image_name and tag from full_image_name
# Your code here

Need a hint?

First split by '/' to remove the registry, then split by ':' to separate the tag.

4

Print the extracted image name and tag

Write two print statements to display the values of image_name and tag.

Docker

full_image_name = "docker.io/library/ubuntu:22.04"
default_registry = "docker.io"
image_with_tag = full_image_name.split("/", 1)[1]
image_name, tag = image_with_tag.split(":")
# Print image_name and tag
# Your code here

Need a hint?

Use print(image_name) and print(tag) to show the results.