Service discovery with AWS Cloud Map

README.md

This gist provides a sample terraform configuration to use service discovery for ecs service. It is useful when configuring a service that is only accessible internally without having to configure ELB and Route 53.

1. Create service discovery namespace
2. Create service discovery configuration A for service B
3. Create ECS service B to resiger with discovery configuration A
4. Access service B using dns name

This will automatically register new ECS tasks with Cloud Map when scaling in/out

application.yml

spring:
  ...
  jpa:
    properties:
      hibernate:
        search:
          backend:
            uris: http://elasticsearch.prod:9200

service_discovery.tf

resource "aws_service_discovery_private_dns_namespace" "service_discovery" {
  name = "prod"
  vpc  = aws_vpc.default.id
}

resource "aws_service_discovery_service" "elasticsearch" {
  name  = "elasticsearch"
  dns_config {
    dns_records {
      ttl  = 60
      type = "A"
    }
    namespace_id   = aws_service_discovery_private_dns_namespace.service_discovery.id
    routing_policy = "MULTIVALUE"
  }
  health_check_custom_config {
    failure_threshold = 1
  }
}

services.tf

resource "aws_ecs_service" "elasticsearch" {
  name    = "elasticsearch"
  ..
  service_registries {
    registry_arn = aws_service_discovery_service.elasticsearch.arn
  }
  ..
}