Pre-requisites

You will need all of the following in order to complete this lab:

Three nodes running Docker v1.12.x(+).

1. Create Machine -

Docker Machine is a tool that lets you install Docker Engine on virtual hosts, and manage the hosts with docker-machine commands. You can use Machine to create Docker hosts on your local Mac or Windows box, on your company network, in your data center, or on cloud providers like AWS or Digital Ocean.

docker-machine create --driver virtualbox manager

docker-machine create --driver virtualbox worker1

docker-machine create --driver virtualbox worker2

eval $(docker-machine env manager)

docker-machine ls (* is active)

Example - 192.168.99.100:2376 manager

192.168.99.101:2376 worker1

192.168.99.102:2376 worker2

You could open three terminal for VM(s)

docker-machine ssh manager

docker-machine ssh worker1

docker-machine ssh worker2

2. Pull Image from Docker Hub -

docker pull rahulsharesth/myimage

3. Run the App -

docker run -itd --name cat-app -p 8000:5000 rahulsharesth/myimage

docker container ls

Open browser - http://192.168.99.100:8000

4. Create the Swarm

docker swarm init --advertise-addr 192.168.99.100:2376

5. Join the Swarm

docker-machine ssh worker1

docker swarm join --token <<>> 192.168.99.100

docker-machine ssh worker2

docker swarm join --token <<>> 192.168.99.100

6. Create Network -

docker-machine ssh manager

docker node ls

docker network create -d overlay catnet

docker network ls

6. Create Service -

docker service create --name cat-app --network catnet -p 8000:5000 rahulsharesth/myimage

http://192.168.99.101:8000 // Worker node is up

http://192.168.99.102:8000 // Worker node is up

7. Scale the app -

Demand is crazy! Everybody loves your cats app! It's time to scale out.

One of the great things about services is that you can scale them up and down to meet demand. In this step you'll scale the web front-end service up and then back down.

docker-machine ssh manager

Scale the number of containers in the web service to 7 with the docker service update --replicas command. replicas is the term we use to describe identical containers providing the same service.

docker service update --replicas 7 cat-app

docker service ls

docker service ps <<>>

8. Check the containers -

docker-machine ssh worker1

docker container ls

docker-machine ssh worker2

docker container ls