在服务发现名称空间（私有托管区域）中注册AWS ECS任务

Question

I'm quite bad at using AWS but I'm trying to automate the set up of an ECS cluster with private DNS names in route53, using the new service discovery mechanism. I am able to click my way through the AWS UI to accomplish a DNS entry showing up in a private hosted zone but I cannot figure out the JSON parameters to add to the json for the command below to accomplish the same thing.

aws ecs create-service --cli-input-json file://aws/createService.json

and below is the approximate contents of the createService.json referenced above

  "cluster": "clustername",
  "serviceName": "servicename",
  "taskDefinition": "taskname",
  "desiredCount": 1,

  // here is where I'm guessing there should be some DNS config referencing some
  // namespace or similar that I cannot figure out...

  "networkConfiguration": {
    "awsvpcConfiguration": {
      "subnets": [
        "subnet-11111111"
      ],
      "securityGroups": [
        "sg-111111111"
      ],
      "assignPublicIp": "DISABLED"
    }
  }

I'd be grateful for any ideas since my googling skills apparently aren't good enough for this problem as it seems. Many thanks!

Answer 1

To automatically have an ECS service register instances into a servicediscovery service you can use the serviceRegistries attribute. Add the following to the ECS service definition json:

{ 
    ...
    "serviceRegistries": [
       {
          "registryArn": "arn:aws:servicediscovery:region:aws_account_id:service/srv-utcrh6wavdkggqtk"
       }
    ]
}

The attribute contains a list of autodiscovery services that should be updated by ECS when it creates or destroys a task as part of the service. Each registry is referenced using the ARN of the autodiscovery service.

To get the Arn use the AWS cli command aws servicediscovery list-services

Strangely the documentation of the ECS service definition does not contain information about this attribute. However this tutorial about service discovery does.

Answer 2

As it turns out there is no support in ecs create service for adding it to the service registry, ie the route53 private hosted zone. Instead I had to use aws servicediscovery create-service and then servicediscovery register-instance to finally get an entry in my private hosted zone.

This became a quite complicated solution so I'll instead give Terraform a shot at it since I found they recently added support for ECS service discovery and see where that takes me...