• Credits: https://github.com/StephenGrider
• Check out his Awesome course on Udemy!

An Example of a Docker / Kubernetes Workflow

Working with Docker

• Create seperate folders for your microservices (In this example, client=frontend, server=backend, worker=intermediary)
• Create your development Dockerfile (Dockerfile.dev)
• Create your production Dockerfile (Dockerfile)
  • In this case we use an nginx webserver in productio but not in development

What about Docker Compose?

• Create a docker-compose.yml file that captures all of the different images needed for your application
• Specify build contexts in respective directions
• Specify environment variables
• Ensure you specify your volumes based on your project directory
• Ensure your application is restarted when changes to the source code are made. (#nodemonIsAwesome)

Details

version: '3'
services:
  postgres:
    image: 'postgres:latest'
  redis:
    image: 'redis:latest'
  nginx:
    restart: always
    build:
      dockerfile: Dockerfile.dev
      context: ./nginx
    ports:
      - '3050:80'
  api:
    build:
      dockerfile: Dockerfile.dev
      context: ./server
    volumes:
      - /app/node_modules
      - ./server:/app
    environment:
      - REDIS_HOST=redis
      - REDIS_PORT=6379
      - PGUSER=postgres
      - PGHOST=postgres
      - PGDATABASE=postgres
      - PGPASSWORD=postgres_password
      - PGPORT=5432
  client:
    build:
      dockerfile: Dockerfile.dev
      context: ./client
    volumes:
      - /app/node_modules
      - ./client:/app
  worker:
    environment:
      - REDIS_HOST=redis
      - REDIS_PORT=6379
    build:
      dockerfile: Dockerfile.dev
      context: ./worker
    volumes:
      - /app/node_modules
      - ./worker:/app

Test your Application

• When you're ready write your unit / functional tests

Details

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

it('renders without crashing', () => {});

Onwards to CI / CD (Travis)

• Create a travis account
• Download the travis CLI (Will be required for deployment to major cloud providers)
• Build your images and push to docker hub upon successful testing.
• Optionally deploy your application to a cloud provider

Details

sudo: required
services:
  - docker

before_install:
  - docker build -t stephengrider/docker-react -f Dockerfile.dev .

script:
  - docker run stephengrider/docker-react npm run test -- --coverage

deploy:
  provider: elasticbeanstalk
  region: "us-west-2"
  app: "docker"
  env: "Docker-env"
  bucket_name: "elasticbeanstalk-us-west-2-306476627547"
  bucket_path: "docker"
  on:
    branch: master
  access_key_id: $AWS_ACCESS_KEY
  secret_access_key:
    secure: "$AWS_SECRET_KEY"

Onwards to Kubernetes

• Install our handy dandy Minikube
• Run your first k8s commands
  • kubectl get pods
• Learn your kubernetes object basics
  • Pods
  • Services
  • Volumes
  • Namespaces
  • Deployments
• Learn about how to handle outside traffic using Ingress

Write Some (Probably a lot) YAML

• For examples see the k8s folder.

Road to Production

• Choose a cloud provider (I prefer GKE). Learn More
• Create your kubernetes cluster
• Create a service account for your kubernetes cluster and provide it admin permissions. Learn More
• Encrypt this service account credentials and upload them to travis
  • travis encrypt-file <service-account-creds>.json -r <githubUserName>/<repo>
  • Add command provided to your build (e.g. openssl aes-256-cbc -K $encrypted_0c35eebf403c_key -iv $encrypted_0c35eebf403c_iv -in service-account.json.enc -out service-account.json -d)
• Install helm (Optional, but makes life much easier)
• Install ingress-nginx from helm
• Update your .travis.yml with a deploy script

Details

docker build -t desainis/multi-client:latest -t desainis/multi-client:$SHA -f ./client/Dockerfile ./client
docker build -t desainis/multi-server:latest -t desainis/multi-server:$SHA -f ./server/Dockerfile ./server
docker build -t desainis/multi-worker:latest -t desainis/multi-worker:$SHA -f ./worker/Dockerfile ./worker
docker push desainis/multi-client:latest
docker push desainis/multi-server:latest
docker push desainis/multi-worker:latest

docker push desainis/multi-client:$SHA
docker push desainis/multi-server:$SHA
docker push desainis/multi-worker:$SHA

kubectl apply -f k8s
kubectl set image deployments/server-deployment server=desainis/multi-server:$SHA
kubectl set image deployments/client-deployment client=desainis/multi-client:$SHA
kubectl set image deployments/worker-deployment worker=desainis/multi-worker:$SHA

• Commit some changes to your code and walk away.
• If you're wondering what $SHA is, it is neat trick to tag your build images with the latest commit's SHA signature. (i.e. what you see when you run git log) It is used to identify when a new image is built and pushed to docker hub. The latest tag will not work from each push as it is not unique and kubernetes will not pick up any changes. (Neat right !?)