How to maintain sticky session(session persistence) with docker swarm?

Question

I have one Java based web application which is deployed in jboss-10.1.0(wildfly). I am using docker swarm mode(docker version 1.12.1) to scale my application everything works perfectly but the only issue I am facing is session management.

Now let's take scenario.

I have two instance is running for my application(i.e. App1 and App2).I am using default load balancer provided by docker swarm mode with nginx to redirect my application from chintan.test.com:9080 to chintan.test.com:80 so that I don't need to write down port with my url and I am able to access directly with this URL chintan.test.com.

Now the default load balancer is using RR(Round-Robin algorithm) to serve my web request.So first time I visit the chintan.test.com it goes to App1 instance and display login page I login with credentials and everything works perfectly after few minutes it's switch to App2 and again the login page comes.

Is there any way or tools(should be Open-source) through which I handle sessions ? So at least I login to App1 and stick to App1 until I logout.

Thank you!

Answer 1

Tried using Nginx and HA-Proxy but none of them seems to be work well in SWARM mode. Then I used Traefik in Docker Swarm and it did the trick for me.The only constraint is that Traefik should run on manager node as it needs to be aware of new worker nodes being added or removed. It doesn't require restart also even if you scale up service, add nodes etc.

I have tested the configuration with Docker compose version 3 which is the latest and deployed using Docker stack deploy.Step by step instructions are over here

To start off you need to create a docker-compose.yml (version 3) and add the load balancer Traefik Image. This is how it looks like

   loadbalancer:
image: traefik
command: --docker \
  --docker.swarmmode \
  --docker.watch \
  --web \
  --loglevel=DEBUG
ports:
  - 80:80
  - 9090:8080
volumes:
  - /var/run/docker.sock:/var/run/docker.sock
deploy:
  restart_policy:
    condition: any
  mode: replicated
  replicas: 1
  update_config:
    delay: 2s
  placement:
     constraints: [node.role == manager]

and then the Image for which you need session stickiness

whoami:
image: tutum/hello-world
networks:
  - net
ports:
  - "80"
deploy:
  restart_policy:
    condition: any
  mode: replicated
  replicas: 5
  placement:
    constraints: [node.role == worker]
  update_config:
    delay: 2s
  labels:
    - "traefik.docker.network=test_net"
    - "traefik.port=80"
    - "traefik.frontend.rule=PathPrefix:/hello;"
    - "traefik.backend.loadbalancer.sticky=true"

You can follow this link for a detailed explanation.