Docker

Introduction

Docker is a platform for developing, shipping, and running applications inside lightweight, portable containers. It enables developers to package applications with all dependencies and run them in any environment.

Installation

Windows

1. Download Docker Desktop from Docker’s official website .
2. Run the installer and follow the on-screen instructions.
3. Restart your system if necessary.

Linux (Debian-based)

sudo apt update
sudo apt install -y docker.io
sudo systemctl enable --now docker

macOS

1. Download and install Docker Desktop from Docker’s official website .
2. Follow the installation instructions.

Basic Commands

Check Docker Version

docker --version

Running a Container

docker run -d -p 80:80 nginx

Listing Running Containers

docker ps

Stopping a Container

docker stop <container_id>

Removing a Container

docker rm <container_id>

Listing Images

docker images

Removing an Image

docker rmi <image_id>

Dockerfile

A Dockerfile is a script containing a series of instructions on how to build a Docker image.

Example Dockerfile

FROM node:18
WORKDIR /app
COPY . .
RUN npm install
CMD ["npm", "start"]

Building an Image

docker build -t myapp .

Running a Container from an Image

docker run -p 3000:3000 myapp

Docker Compose

Docker Compose allows managing multi-container applications using a YAML file.

Example docker-compose.yml

version: "3"
services:
  web:
    image: nginx
    ports:
      - "80:80"
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: example

Running Docker Compose

docker-compose up -d

Stopping Docker Compose

docker-compose down

Networking in Docker

Listing Networks

docker network ls

Creating a Network

docker network create mynetwork

Connecting a Container to a Network

docker network connect mynetwork mycontainer

Volumes in Docker

Creating a Volume

docker volume create myvolume

Listing Volumes

docker volume ls

Using a Volume in a Container

docker run -v myvolume:/data busybox