Swarm JMeter Demo

The purpose of this demo is to demonstrate that a service running in a Docker swarm can withstand a greater load (tested with load-testing software JMeter) than an individual container.

Steps

Swarm Mode

Create a docker image based off the dockerfile:

docker build -t swarm-jmeter-demo .

To test it locally, run:

 docker run -d -p 9000:9000 --name swarm-jmeter-demo swarm-jmeter-demo
 curl localhost:9000/random

And you should get a response. Take down the container after this

docker stop swarm-jmeter-demo

Set up a local registry to host your image

docker run -d -p 5000:5000 --restart=always --name registry registry:2

Tag your image to point to the registry:

docker tag swarm-jmeter-demo localhost:5000/swarm-jmeter-demo

Push your image to your registry.

docker push localhost:5000/swarm-jmeter-demo

Test it by running

docker run -d -p 9000:9000 --name swarm-jmeter-demo localhost:5000/swarm-jmeter-demo

Create 3 virtual machines with 600 mb of RAM (so they are quickly overwhelmed)

docker-machine create --driver virtualbox --virtualbox-memory 600 manager1
docker-machine create --driver virtualbox --virtualbox-memory 600 worker1
docker-machine create --driver virtualbox --virtualbox-memory 600 worker2

NOTE: If the creation of the docker-machine hangs, try giving them more memory.

Before we get any further, let's set up port forwarding for the manager node. We can do this either with the GUI or the CLI2 We need port 9000 available, because that is the port for our web server.

VBoxManage modifyvm "manager1" --natpf1 rule1,tcp,,9000,,9000

Get the IP address of the manager

docker-machine ip manager1

Ours is 192.168.99.100

SSH into the manager node to create the swarm

docker-machine ssh manager1

Initialize the swarm

$ docker swarm init --advertise-addr <manager1-ip>
Swarm initialized: current node (dizg6iq1tt848dj0qn4y77pff) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join \
    --token SWMTKN-1-1q5pk2o0qbf2o1l6ug6xdw1b9xq1ou8iehsslrl02fs8h1kw15-1d1qm3t15bjn0z4crjuvciadl \
    <manager1-ip>:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

In another terminal, ssh into another worker node, and join the swarm.

docker-machine ssh worker1
docker swarm join \
    --token SWMTKN-1-1q5pk2o0qbf2o1l6ug6xdw1b9xq1ou8iehsslrl02fs8h1kw15-1d1qm3t15bjn0z4crjuvciadl \
    <manager1-ip>:2377

Do this for both nodes. To verify that they have joined the swarm, run docker node ls in manager1 to see all the nodes.

ssh into the manager1, and modify the docker configs to allow our insecure registry:

sudo vi /etc/docker/daemon.json

And add in the following, where the ip address is the ip address of your local host running the registry.

{ "insecure-registries":["<local-host-ip>:5000"] }

And then restart the daemon:

sudo /etc/init.d/docker restart

You will need to repeat these steps also for worker1 and worker2.

Test that the container can be fetched inside a worker node from your local repository (replacing the ip address with your local host ip address):

docker run -d -p 9000:9000 --name swarm-jmeter-demo <local-host-ip>:5000/swarm-jmeter-demo

And make sure it is accessable locally on that node:

curl localhost:9000/random

Now you can start your service with the manager. First, we want to create an overlay network so the different nodes are accessible, and then we want to create the service in that network.

docker network create -d overlay swarm-demo

docker service create --replicas 1 --name swarm-jmeter-demo --network swarm-demo -p 9000:9000 <local-host-ip>:5000/swarm-jmeter-demo

You can check it out to see information by running:

docker service inspect --pretty swarm-jmeter-demo

And see which nodes are running the service by running:

docker service ps swarm-jmeter-demo

We want to scale the service. Let's do five instances.

docker service scale swarm-jmeter-demo=3

And to see what nodes are running (as an example)

$ docker service ps swarm-jmeter-demo
3l7vx4b14zozr9v8cvkqrx5e6  swarm-jmeter-demo.1  192.168.0.74:5000/swarm-jmeter-demo  worker1   Running        Running 22 seconds ago  
boomt2wwm3d0jrrgzeuwmg488  swarm-jmeter-demo.2  192.168.0.74:5000/swarm-jmeter-demo  manager1  Running        Running 9 seconds ago   
0g56w8he4zkdmt39simdjyqm4  swarm-jmeter-demo.3  192.168.0.74:5000/swarm-jmeter-demo  worker2   Running        Running 8 seconds ago   
35scnhi2m5hyie8qflvqpdkc6  swarm-jmeter-demo.4  192.168.0.74:5000/swarm-jmeter-demo  worker2   Running        Running 8 seconds ago   
01gvf46qmn0y7zhvmnic7bwxx  swarm-jmeter-demo.5  192.168.0.74:5000/swarm-jmeter-demo  worker1   Running        Running 9 seconds ago 

Single Container Mode (Non-swarm)

With the images built following the instructions in the swarm mode, it is simple to get a single container running. If the swarm is still running, turn it off with:

docker service rm swarm-jmeter-demo

Then, on the manager1 virtual machine, run:

docker run -d -p 9000:9000 --name swarm-jmeter-demo <local-host-ip>:5000/swarm-jmeter-demo

Load Testing

Run jmeter, and open ./jmeter-tests/HTTP Request.jmx and click run. This will create 300 threads to create requests against the cluster. If you check the Thread Group's "View Results in Table", you can see a summary of the samples, including some summary statistics.