Learn DOCKER with Real Code Examples

Docker uses containerization to isolate applications and their dependencies from the host system.

Supports building images with Dockerfiles and running containers from those images.

Provides networking, storage, and orchestration primitives to manage containers.

Integrates with CI/CD pipelines for automated builds and deployments.

Optimizes resource utilization compared to traditional virtual machines.

Docker Engine - runtime for building and running containers

Docker Images - snapshot of an app and its dependencies

Docker Containers - running instances of images

Dockerfile - declarative instructions to build images

Docker Compose - define and run multi-container apps

Image - immutable snapshot of an application and its dependencies

Container - running instance of an image

Volume - persistent storage for containers

Network - allows communication between containers

Dockerfile - script for building images

Dockerfile - defines image build steps

docker-compose.yml - defines multi-container setups

src/ - application source code

configs/ - environment-specific configurations

data/ - optional persistent volumes

Write Dockerfile defining app and dependencies

Build image using `docker build`

Run container using `docker run`

Attach volumes or networks as needed

Test and deploy containerized app

Beginner: containerize a simple app

Intermediate: multi-container app with Compose

Advanced: CI/CD integration and automated builds

Expert: production deployment with Swarm or Kubernetes

Enterprise: large-scale microservices with monitoring and scaling

Docker vs Virtual Machines: Docker more lightweight, faster startup, shares OS kernel

Docker vs Podman: Podman daemonless, rootless; Docker mature ecosystem

Docker vs LXC: Docker focused on application containers; LXC system containers

Docker vs Kubernetes: Kubernetes orchestrates containers; Docker builds/runs them

Docker vs Singularity: Singularity designed for HPC, Docker for general-purpose apps

2013 - Docker initial release by Solomon Hykes

2014 - Docker 1.0 stable

2015 - Docker Compose introduced

2017 - Docker Swarm integrated for orchestration

2025 - Latest Docker CE/EE with modern container features

Image - template containing app and dependencies

Container - running instance of an image

Volume - persistent storage for containers

Network - communication channel for containers

Dockerfile - instructions to build an image