Assignment: Create A Multi-Service Multi-Node Web App

Goal: create networks, volumes, and services for a web-based "cats vs. dogs" voting app.

• See architecture.png in this directory for a basic diagram of how the 5 services will work
• All images are on Docker Hub, so you should use editor to craft your commands locally, then paste them into swarm shell (at least that's how I'd do it)
• a backend and frontend overlay network are needed. Nothing different about them other then that backend will help protect datatbase from the voting web app. (similar to how a VLAN setup might be in traditional archecture)
• The database server should use a named volume for perserving data. Use the new --mount format to do this: --mount type=volume,source=db-data,target=/var/lib/postgresql/data

Services (names below should be service names)

• vote

  • dockersamples/examplevotingapp_vote:before
  • web front end for users to vote dog/cat
  • ideally published on TCP 80. Container listens on 80
  • on frontend network
  • 2+ replicas of this container docker service create --name vote -p 80:80 --network frontend --replicas 2 dockersamples/examplevotingapp_vote:before

• redis

  • redis:3.2
  • key/value storage for incoming votes
  • no public ports
  • on frontend network
  • 1 replicas docker service create --name redis --network frontend redis:3.2

• worker

  • dockersamples/examplevotingapp_worker
  • backend processor of redis and storing results in postgres
  • no public ports
  • on frontend and backend networks
  • 1 replica docker service create --name worker --network frontend --network backend dockersamples/examplevotingapp_worker

• db

  • postgres:9.4
  • one named volume needed, pointing to /var/lib/postgresql/data
  • on backend network
  • 1 replica docker service create --name db --network backend --mount type=volume,source=db-data,target=/var/lib/postgresql/data postgres:9.4

• result

  • dockersamples/examplevotingapp_result:before
  • web app that shows results
  • runs on high port since just for admins (lets imagine)
  • so run on a high port of your choosing (I choose 5001), container listens on 80
  • on backend network
  • 1 replica docker service create --name result --network backend -p 5001:80 dockersamples/examplevotingapp_result:before