elixir-ecs

This repository is a minimal setup of an elixir application running on multiple connected nodes on aws as fargate services. Each instance has a cron job that depending on the configuration can run on every node, on one node of the service or on one node of connected nodes.

The services are called krillin and vegeta so that they can be distinguished while testing and analyzing the logs.

This repository contains:

• an elixir application with a quantum cron job
• an aws infrastructure with two fargate services
• a service discovery to connect the ecs service's instances/nodes
• in the final deployment, the jobs run in only once instance of all connected

Getting started with docker

• Build and run: docker-compose build && docker-compose up
• In the browser call one of: localhost:4000, localhost:4000/krillin, localhost:4001, localhost:4001/krillin
• You will see the node and the connected nodes. Beware of the configuration in the docker-compose

Getting started on aws

• Build docker image: docker build --progress=plain -t elixir-ecs:latest .
• Deploy infrastructure
  • cd infrastructure && npm i && npm run build && cdk deploy
  • Right after the ECR repo is created, you will have to push your docker image to ECR so that the ECS service finds them when it tries to start:

  docker tag elixir-ecs:latest AWS_ACCOUNT.dkr.ecr.AWS_REGION.amazonaws.com/elixir-ecs:latest
  docker push AWS_ACCOUNT.dkr.ecr.AWS_REGION.amazonaws.com/elixir-ecs:latest  
  

• when the deployment is done you will see the load balancer url LB_URL on the console

Viewing the data

The two "services" one is shown with LB_URL and the other with LB_URL/krillin.

They display the current node and the connected nodes. Per default only the nodes within a service are connected.

Connecting all nodes of all services

• go to lib/app-resources.ts:37
• change the configuration so that all nodes have the same name and query for the same name
• build and deploy the infrastructure again

Jobs

The jobs run once per cluster. This means that if all nodes are connected, the jobs will run only in one instance of all services. If only the instances within a node are connected, the job will run on one instance of each service.

the logs will show something like:

19:00:10.643 [info] Job running on: :"vegeta-service-dbz@172.31.25.17" with cookie :"my-cookie" from possible hosts: [:"vegeta-service-dbz@172.31.11.177"]
19:00:10.646 [info] Job running on: :"dbz@172.31.1.110" with cookie :"my-cookie" from possible hosts: [:"dbz@172.31.23.124"]
19:00:15.643 [info] Job running on: :"vegeta-service-dbz@172.31.25.17" with cookie :"my-cookie" from possible hosts: [:"vegeta-service-dbz@172.31.11.177"]
19:00:15.646 [info] Job running on: :"dbz@172.31.1.110" with cookie :"my-cookie" from possible hosts: [:"dbz@172.31.23.124"]
19:00:20.644 [info] Job running on: :"vegeta-service-dbz@172.31.25.17" with cookie :"my-cookie" from possible hosts: [:"vegeta-service-dbz@172.31.11.177"]
19:00:20.646 [info] Job running on: :"dbz@172.31.1.110" with cookie :"my-cookie" from possible hosts: [:"dbz@172.31.23.124"]
19:00:25.259 [info] Job running on: :"krillin-service-dbz@172.31.22.8" with cookie :"my-cookie" from possible hosts: [:"krillin-service-dbz@172.31.6.25"]
19:00:25.643 [info] Job running on: :"vegeta-service-dbz@172.31.25.17" with cookie :"my-cookie" from possible hosts: [:"vegeta-service-dbz@172.31.11.177"]
19:00:25.646 [info] Job running on: :"dbz@172.31.1.110" with cookie :"my-cookie" from possible hosts: [:"dbz@172.31.23.124"]