Demo Notes

Docker Demo - from zero to scalable and redundant (build, ship, scale)
Adapted from (https://docs.docker.com/get-started/part5/)

Part 1: a basic container with nginx

docker run --name docker-nginx -p 999:80 -d nginx

Now we should have the Nginx server running here http://localhost:999

in a different world, I'd have to have an operating system, system libraries, running a ton of stuff, in this case my only dependency is docker, but running a web server isn't enough, modern architectures are a little bit more complex so let me show you more!

Part 2: Build a Dockerfile to Customize our Container

We'll build a Dockerfile so that we can custimize our container with a little message

#Dockerfile 
FROM nginx
RUN echo '<h1>Hello World!</h1>' > /usr/share/nginx/html/index.html

Build and Run the Container

docker build -t docker-nginx .
docker run -p 9999:80 docker-nginx

Now we should have the Nginx server running here http://localhost:9999

Part 3: Push Image to Repo

We want others to be able to see our image, in my case I pushed the image to Docker's public hub, could be private or you can run your own hub internally
docker push ernestoongaro/demos
You will now see it at https://hub.docker.com/r/ernestoongaro/demos/

##Part 4: Complexity!

Great, now we're cooking with fire, and this would be enough of an infrastructure to run a static (web 1.0 site), but in reality we have a more complex app that requires more than one service
We'll create a docker Compose file - it will set up a network with auto load balancing and manage multiple images

#docker-compose.yml
version: "3"
services:
  nginx:
    image: nginx
    deploy:
      replicas: 5
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
      restart_policy:
        condition: on-failure
    ports:
      - "99:80"
    networks:
      - webnet
  visualizer:
    image: dockersamples/visualizer:stable
    ports:
      - "8888:8080"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
    deploy:
      placement:
        constraints: [node.role == manager]
    networks:
      - webnet
networks:
  webnet:

Check this into Github, now anybody can set this up on a different machine (this is the control part!)
Finally, we can run our service

docker-compose up

Part 5: Scale

We now want to scale our service and run it here or on the cloud
First we initalize our "swarm" which is Docker's way to run an entire cluster
docker swarm init

Second, we deploy our services to the swarm

docker stack deploy -c docker-compose-complex.yml docker-nginx-swarm

checks status

docker stack ps docker-ngnix-swarm

docker service ls

http://localhost:8888

Scattered Notes

docker stack rm docker-nginx-swarm