Is AWS ECS with Terraform broken? - amazon-web-services

Question

I am trying to spin up an ECS cluster with Terraform, but can not make EC2 instances register as container instances in the cluster.
I first tried with the verified module from Terraform, but this seems out dated (ecs-instance-profile has wrong path).
Then I tried with another module from anrim, but still no container instances. Here is the script I used:
provider "aws" {
region = "us-east-1"
}
module "vpc" {
source = "terraform-aws-modules/vpc/aws"
version = "2.21.0"
name = "ecs-alb-single-svc"
cidr = "10.10.10.0/24"
azs = ["us-east-1a", "us-east-1b", "us-east-1c"]
private_subnets = ["10.10.10.0/27", "10.10.10.32/27", "10.10.10.64/27"]
public_subnets = ["10.10.10.96/27", "10.10.10.128/27", "10.10.10.160/27"]
tags = {
Owner = "user"
Environment = "me"
}
}
module "ecs_cluster" {
source = "../../modules/cluster"
name = "ecs-alb-single-svc"
vpc_id = module.vpc.vpc_id
vpc_subnets = module.vpc.private_subnets
tags = {
Owner = "user"
Environment = "me"
}
}
I then created a new ecs cluster (from the aws console) on the same VPC and carefully compared the differences in resources. I managed to find some small differences, fixed them and tried again. But still no container instances!
A fork of the module is available here.

Answer 1

Can you see instances being created in the autoscaling group? If so, I'd suggest SSHing to one of them (either directly or using a bastion host, eg. see this module) and checking ECS agent logs. In my experience those problems are usually related to IAM policies, and that's pretty visible in logs but YMMV.