Docker Cheat Sheet.md

Docker Cheat Sheet

• docker image - is a standalone, executable file used to create a docker container

  # Creates an image
  $ docker build -t <app-name> .

• docker container - a lightweight, standalone, executable software package that includes everything needed to run a piece of software

  # Starts the container
  $ docker run -dp 5010:5010 my-flask-app
  
  # docker compose alternative
  $ docker-compose up -d

• Cloud Container Registry container registry - a repository—or collection of repositories—used to store and access container images.

• Running docker container

  $ docker run -it --memory=1g --memory-swap=1g --memory-swappiness=0 --cpus=4 --entrypoint=/bin/bash debugsession
  $ docker run -it --privileged --name mockserver mockserver /bin/sh

• Sign into docker

  $ docker login -u YOUR-USER-NAME
  

• Push your image

  $ docker push <namespace>/<image>:<tag>
  

• Pull your image

  $ docker pull <namespace>/<image>:<tag>
  

• Creating networks

  $ docker network create my-network

DinD (Docker in Docker)

1. Copy the contents of this docker and save it onto your local machine

   # Filename: server.dockerfile
   
   # Use the Docker-in-Docker image as the base image
   FROM docker:20.10-dind
   
   # Install any additional tools you might need in the remote server container
   # For example, you can install utilities such as curl, wget, etc.
   RUN apk update && apk add --no-cache curl wget 
   
   # Create working directory and copy files needed for your server
   WORKDIR /app
   COPY ./app .
   
   # Entry point to start the Docker daemon
   # The Docker daemon will run as the primary process in the container
   CMD ["dockerd-entrypoint.sh"]
   

2. Execute the following commands in the terminal where your docker file is located.

   # Build docker image
   $ docker build -t mock-server -f server.dockerfile .
   
   # Run your container
   $ docker run --privileged --name testing -d mock-server
   
   # Remote into your outer docker container
   $ docker exec -it testing sh
   
   # Test your inner docker API is working with a CURL command
   $ curl -X GET http://127.0.0.1:5010/health

Terminology

• Docker Image - a snapshot or blueprint of the libraries and dependencies required inside a container for an application to run. These images are read-only for the purpose of creating Docker Containers
• Docker Container - a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another