Docker Image Build and Deployment

docker buildx build command

Overview

docker buildx build is an extended version of the traditional docker build command, offering multi-architecture builds and advanced build options.

• This allows you to build images for multiple platforms such as x86 and ARM in a single command.
• Basically Build = Making a Docker Image

• Used to use just build in the past
  • buildx is an expanded version of build, it has build kit
• Docker Commands

Basic Structure

my-app/
 ├── src/
 ├── Dockerfile
 └── ...

Basic Usage Example

Initially, you need to ensure you have a buildx builder instance ready. (This is a one time setup)

# Create a new builder instance
docker buildx create --name mybuilder --use
 
# (Optional) Inspect the builder
docker buildx inspect --bootstrap

# Build an image using the Dockerfile in the current directory (.)
# -t : specify tag
# --platform : specify target platforms
# --push : push to registry after build
 
docker buildx build \
  --platform linux/amd64,linux/arm64 \
  -t username/my-app:1.0.0 \
  .

Option	Description
--platform	Specify platforms to build (comma-separated)
-t	Specify image name and tag
--push	Automatically push to registry after build - default is Docker Hub
--load	Load the built image into the local Docker engine

You have to know --platform, --t, --push, --load

• Tips
  • On M1/M2 Macs, use --platform linux/amd64 to test with the same architecture as the server.
  • When building multi-architecture images, use --push to upload the manifest list to the registry.

Summary

Keyword	Summary
buildx	Provides extended build features (uses BuildKit)
—platform	Specify architecture
—push	Push after build

Image Tagging

Tagging

Tags are identifiers that distinguish image versions and purposes. You can assign multiple tags to the same image to easily separate development and production environments.

# <registry>/<username>/<image>:<tag>
docker tag my-app:latest username/my-app:1.0.0

• docker tag my-app:latest (1) username/my-app:1.0.0 (2)
  • 1 = original
  • 2 = new tag

Component	Example	Description
Registry	docker.io	Defaults to DockerHub
Username	username	DockerHub account name
Image Name	my-app	Application name
Tag	1.0.0	Version information

• Tips
  • Use latest mainly for development/testing.
  • Use versioned tags like 1.0.0 in production.
  • Manage environment-specific tags like dev, staging, prod alongside version tags.

Summary

Tag	Purpose
latest	Latest build
1.0.0	Fixed version
dev	Development

DockerHub Deployment

docker login # Enter username and password
docker push username/my-app:1.0.0

1. Create a DockerHub account and log in.
2. Build and tag the image locally
3. Upload using docker push.
4. Verify the image on DockerHub web interface.

Tips

• In CI/CD pipelines, use DOCKER_USERNAME and DOCKER_PASSWORD environment variables for automated build & push.
• When using private repositories, manage account permissions carefully.