Docker Commands Cheat Sheet

This document provides a simple explanation of essential Docker commands, organized into logical sections for easy reference.

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Introduction

Docker is a platform for developing, shipping, and running applications in containers.

Key Concepts:

• Containers: Lightweight, portable units that package an application and its dependencies.
• Images: Read-only templates used to create containers, containing the application code and libraries.
• Docker Swarm: A clustering and orchestration tool for managing a group of Docker engines.

This guide covers the most commonly used Docker commands.

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Basic Commands

These commands form the foundation of working with Docker:

• Check Docker Version:
  docker --version
  Verify the installed Docker version.

• Run a Container:
  docker run hello-world
  Run a container from an image. If the image is not available locally, it will be pulled from Docker Hub.

• Name a Container:
  docker run --name DragonEmperor9480 <image_name>
  Assign a specific name to a container.

• Interactive Mode:
  docker run -it <image_name>
  Run a container in interactive mode with a terminal.

• Detached Mode:
  docker run -d <image_name>
  Run a container in the background.

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Container Management

Containers are instances of Docker images. Use these commands to manage them:

• Attach to a Container:
  docker attach <container_id>
  Reattach to a running container.

• Run for a Specific Time:
  docker run <image_name> sleep 100
  Run a container for a specified duration before it exits.

• List Running Containers:
  docker ps
  Display all running containers.

• List All Containers:
  docker ps -a
  Display all containers (running and stopped).

• Remove a Container:
  docker rm <container_id>
  Delete a container.

• Stop a Container:
  docker stop <container_id>
  Stop a running container.

• Inspect a Container:
  docker inspect <container_id>
  View detailed information about a container.

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Image Management

Images are the building blocks of containers. These commands help you work with them:

• Pull an Image:
  docker pull <image_name>
  Download an image without running it.

• List Images:
  docker images
  Display all locally available images.

• Remove an Image:
  docker rmi <image_name>
  Delete an image.

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Running Commands in Containers

• Execute a Command:
  docker run ubuntu cat /etc/*release*
  Run a specific command inside a container.

• Use a Specific Image Version:
  docker run ubuntu:16.04
  Run a container using a specific version of an image.

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Resource Management

• Limit CPU Usage:
  docker run --cpu=.5 ubuntu
  Restrict a container to use no more than 50% of CPU.

• Limit Memory Usage:
  docker run --memory=100m ubuntu
  Restrict a container to use no more than 100MB of memory.

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Volumes and Data Persistence

• Create a Volume:
  docker volume create data_volume
  Create a persistent volume for storing data.

• Mount a Volume:
  docker run -v data_volume:/var/lib/mysql mysql
  Mount a volume to a container.

• Mount a Directory:
  docker run -v /data/mysql:/var/lib/mysql mysql
  Mount a specific directory from the host to a container.

• New Mount Syntax:
  docker run --mount type=bind,source=/data/mysql,target=/var/lib/mysql mysql
  Use the newer syntax for mounting directories.

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Networking

• List Networks:
  docker network ls
  Display all Docker networks.

• Inspect a Network:
  docker network inspect bridge
  View detailed information about a network.

• Default Networks:

  • bridge: Default network for containers.
  • none: No network access.
  • host: Use the host's network stack.

• Create a Custom Network:

  docker network create \
    --driver bridge \
    --subnet 182.18.0.0/16 \
    custom-isolated-network

  Create a user-defined network with a specific subnet.

• Example: MySQL Network:

  docker network create \
    --driver bridge \
    --subnet 182.18.0.0/24 \
    --gateway 182.18.0.1 \
    wp-mysql-network

  Create a network for a MySQL database.

• Deploy MySQL:

  docker run --name mysql-db \
    -e MYSQL_ROOT_PASSWORD=db_pass123 \
    --network wp-mysql-network \
    mysql:5.6

  Deploy a MySQL container attached to the custom network.

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Docker Swarm and Orchestration

Docker Swarm allows you to manage a cluster of Docker nodes as a single virtual system:

• Initialize Swarm:
  docker swarm init
  Initialize a Docker Swarm cluster.

• Join Swarm:
  docker swarm join --token <token>
  Join a worker node to the Swarm cluster.

• Create a Service:
  docker service create --replicas=3 my-web-server
  Deploy a service with multiple replicas.

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Storage Drivers

Storage drivers handle how Docker manages image layers and container filesystems. Supported drivers include:

• AUFS
• ZFS
• BTRFS
• Device Manager
• Overlay
• Overlay2

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Conclusion

This cheat sheet provides a quick reference for essential Docker commands. For more detailed information, refer to the official Docker documentation.