docker-workshop

Docker-workshop

reference :

• https://docker-curriculum.com/#webapps-with-docker
• https://github.com/Vizuri/docker-exercises
• https://learndocker.online/courses/
• https://labs.play-with-docker.com/

Docker Commands

list images -

  docker image ls 
  docker images

list running containers -

  docker ps

list containers including stopped containers

  docker ps -a

starting a new container

  docker   run -dit --name web debian
    - i : interactive
    -d : detach
    - t : open tty session
  -- rm : automatically removes the containter when it exits

stop a running container

  docker stop web

remove a container

  docker rm web

inspect container policy

  docker inspect web

force stop a container

  docker kill web

show docker logs

  docker logs -f web  (follow log output)
  docker logs -t web (show timestamp)

start shell of a running container

  docker exec -it 239a /bin/bash

check exposed ports of a docker container

  docker ports static-site

Sample Docker run for PostgreSQL and RabbitMQ

  docker run --name postgres-db -p 5432:5432 -e POSTGRES_PASSWORD=xxxxx -d postgres
  docker run --name rabbit-mq --hostname rmq -p 5672:5672 -p 15672:15672 -e RABBITMQ_DEFAULT_USER=admin -e RABBITMQ_DEFAULT_PASS=xxxxx  -d rabbitmq:3.11-management

Docker volumes : local host directory can be mapped to new/existing directory of docker container using -v handle

  docker run -it --name test1 -v C:\Users\ishan\Documents\docker_test:/data alpine

Docker shorthands with full commands

• docker pull=docker image pull
• docker create=docker container create
• docker start=docker container start
• docker ps=docker container ps
• docker run=docker create;docker start
• docker rmi=docker image rm
• docker rm=docker container rm

Dockerfile for python project

• FROM python base image
• WORKDIR working directory
• COPY files to container
• RUN installation of libraries and modules
• EXPOSE ports
• VOLUME declare mount point in container
• ENV environment variables
• LABEL
• ENTRYPOINT start-up commands
• CMD ... and its arguements

Design Principles for Containerized Apps

• One Application or Component per Container
• Horizontal Scaling
• Application Observability
• Security Framework
• Application Secrets
• Automated Deployment
• Immutable and Disposable Containers
• Application Data in Volumes
• Virtual Networks
• Small Container Images
• Image Tagging

Image Build Procedure

1. Create Source Code
2. Create Container with Base Image
3. Create a Working Directory
4. Copy source code to Working Dir
5. Install Libraries and dependencies
6. Install additional software
7. Commmit the Container to New Image

Running Django on container

Dockerfile

ARG ImageTag=3.7.3
FROM $BaseImage:$ImageTag
ENV PYTHONUNBUFFERED 1
ARG DjangoVersion=2.2.1
RUN pip install Django==$DjangoVersion
WORKDIR /code

Docker build and run

docker build -t django:3.7.3 -f base_image/Dockerfile.mydjango .
docker run --rm -it django:3.7.3 django-admin version
docker run --rm -it -v ${PWD}:/code django:3.7.3 django-admin startproject myproject
docker run --rm -it -v ${PWD}:/code -p 8000:8000 django:3.7.3 python myproject/manage.py migrate
docker run --rm -it -v ${PWD}:/code -p 8000:8000 django:3.7.3 python myproject/manage.py runserver 0:8000