Docker Cheatsheet

What is Docker?

Docker is an open-source platform that automates the deployment, scaling, and management of applications. It achieves this by packaging an application and its dependencies into an isolated, lightweight unit called a container.

Unlike traditional virtual machines that require a full operating system for each application, containers share the host machine's OS kernel. This makes them incredibly fast to start, highly resource-efficient, and easily portable across different environments.

Why Use Docker?

Consistency It solves the classic "it works on my machine" problem. A container behaves exactly the same way in development, testing, and production.
Efficiency Containers are lightweight. They boot up in seconds and consume a fraction of the memory compared to traditional VMs.
Isolation Each container operates independently. You can run different applications with conflicting dependencies on the same host without issues.
CI/CD Ready Docker fits perfectly into continuous integration and delivery pipelines, making automated testing and deployment much smoother.

Commands Reference

Command Description 
docker --version
 Check installed Docker version 
docker info
 Display detailed system-wide Docker info
Command Description 
docker login
 Authenticate with Docker Hub (enter username & password) 
docker tag <image_name> <username>/<repo>:<tag>
 Tag local image for Docker Hub repository 
docker push <username>/<repo>:<tag>
 Push tagged image to Docker Hub 
docker logout
 Log out from Docker Hub
Command Description 
docker build -t <image_name> .
 Build Docker image from Dockerfile 
docker images
 List all local Docker images 
docker rmi <image_name>
 Remove Docker image 
docker pull <image_name>
 Download image from Docker Hub 
docker push <image_name>
 Upload image to Docker Hub
Command Description 
docker run <image>
 Run a container from an image 
docker run -it <image>
 Run container in interactive mode (terminal access) 
docker run -d <image>
 Run container in detached (background) mode 
docker run -p <host_port>:<container_port> <image>
 Bind container port to host port 
docker ps
 List running containers 
docker ps -a
 List all containers (including stopped ones) 
docker stop <container_id>
 Stop a running container 
docker start <container_id>
 Start a stopped container 
docker restart <container_id>
 Restart a container 
docker rm <container_id>
 Remove a stopped container 
docker logs <container_id>
 View logs from container 
docker exec -it <container_id> bash
 Execute bash shell inside a running container 
docker exec -it <container_id_or_name> sh
 Execute shell (sh) in a running container
Command Description 
docker volume create <volume_name>
 Create a named volume 
docker volume ls
 List all volumes 
docker volume inspect <volume_name>
 View detailed info about a volume 
docker volume rm <volume_name>
 Remove a named volume
Command Description 
docker network ls
 List available Docker networks 
docker network create <network_name>
 Create a custom network 
docker network inspect <network_name>
 Inspect network configuration/details 
docker network rm <network_name>
 Remove a Docker network
Command Description 
docker-compose up
 Start all services in docker-compose.yml 
docker-compose up -d
 Start services in detached (background) mode 
docker-compose up --build
 Build images and then start services (recommended after Dockerfile change) 
docker-compose down
 Stop and remove containers, networks, volumes created by Compose 
docker-compose build
 Only build images defined in docker-compose.yml 
docker-compose ps
 List running containers from Compose 
docker-compose logs
 View logs for all services in Compose 
docker-compose logs <service>
 View logs for a specific service 
docker-compose exec <service> sh
 Exec into a running service's shell
Command Description 
docker system prune
 Remove all unused containers, networks, images 
docker container prune
 Remove all stopped containers 
docker image prune
 Remove unused Docker images 
docker volume prune
 Remove unused volumes 
docker stop $(docker ps -q)
 Stop all containers 
docker rmi $(docker images -q)
 Remove all images 
docker rm $(docker ps -aq)
 Remove all containers

When to Use What?

Use docker build when:

  • You are working with a single service app.
  • You are not using docker-compose.
  • You want to manually build a Docker image from a Dockerfile.

Example:

docker build -t my-app-image .
docker run -p 3000:3000 my-app-image

Use docker-compose up --build when:

  • You are managing multiple services (e.g., Node.js, MongoDB, Redis, etc.).
  • You have a docker-compose.yml file and a Dockerfile.
  • You made changes to your Dockerfile or environment variables and need to rebuild.

Recommended Command:

docker-compose up --build

Use this to:

  • Run all services defined in docker-compose.yml in the background (detached mode).
  • You already have images built or don't need to rebuild.

Example:

docker-compose up -d

Use this when:

  • You want to stop and clean up all services, networks, and volumes created by Docker Compose.

Example:

docker-compose down