Docker cookbook

Definition of Container

Containers isolate the application from the environment in which it runs, ensuring that it functions consistently across any platform.

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Definition of Docker

Docker is a containerization platform that automates the creation, deployment, and execution of applications in containers.

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Advantages of Docker

• Consistency between development, testing, and production environments.
• Ease of distribution and scalability.
• Isolation of applications and their dependencies.

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Docker compose

A tool for defining and running multi-container applications. It facilitates the management of containers that depend on one another.

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Best practises

• Use Alpine or minimal images to reduce image size.
• Split the image build process into multiple stages.
• Use volumes for data persistence.
• Avoid hardcoding credentials.

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Dockerfile example

FROM node:20-alpine

WORKDIR /app

COPY package.json ./
RUN pnpm install
COPY . .

CMD ["pnpm", "start"]

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Docker compose example

services:
  postgres:
    image: postgres:16-alpine
    container_name: database_container_name
    environment:
      POSTGRES_USER: ${POSTGRES_USER}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
      POSTGRES_DB: ${POSTGRES_DB}
    ports:
      - "5432:5432"
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 10s
      timeout: 5s
      retries: 5

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Useful commands

Command	Description
docker build -t image_name .	Builds a Docker image from the Dockerfile in the current directory.
docker run -d -p 3000:3000 image_name	Starts a container in the background and maps port 3000 of the container to local port 3000.
docker ps	Shows the list of currently running containers.
docker ps -a	Shows the list of all containers, including stopped ones.
docker start container_name	Starts an existing container that was previously created or stopped.
docker stop container_name	Stops a running container.
docker rm container_name	Removes a stopped container.
docker rmi image_name	Deletes a Docker image.
docker exec -it container_name bash	Accesses an interactive shell inside the container.
docker logs container_name	Displays the logs of a running container.
docker-compose up	Starts all services defined in the docker-compose.yml file.
docker-compose up -d	Starts all services in the background (detached mode).
docker-compose down	Stops and removes all containers, networks, and volumes created by Docker Compose.
docker-compose ps	Shows the status of containers managed by Docker Compose.
docker-compose logs	Displays the logs of all services defined in the docker-compose.yml file.
docker-compose stop	Stops the containers started with Docker Compose without removing them.
docker volume ls	Lists all available Docker volumes.
docker network ls	Lists all available Docker networks.
docker pull image_name	Downloads a Docker image from Docker Hub or another registry.
docker inspect container_name	Shows the details and configuration of a container or Docker image.