@raykrueger/cdk-fargate-public-dns

This is an AWS Cloud Development Kit V2 construct library to support updating Route 53 entry with the public ip address of an ECS Fargate task. This is useful if you are, say, running an individual instance of a game server on ECS Fargate and do not want the added cost of a Network Load Balancer.

Usage

This is the simple usecase. You pass an ECS Service and Cluster defined by your CDK stack. Within the dnsConfig block you pass the Route 53 fully qualified domain name, and the hosted zone ID.

import { PublicIPSupport } from '@raykrueger/cdk-fargate-public-dns';

new PublicIPSupport(stack, 'PublicIPSupport', {
    cluster,
    service,
    dnsConfig: {
        domainName: 'www.example.com',
        hostzedZone: 'Z0000000000000000000X',
    },
})

Usage in Another Account

If the hosted zone you want to update is in a different AWS acccount, this Construct can assume a role in that target account in order to perform the Route 53 Domain update. To do that, simply add the assumedRole property to the dnsConfig.

new PublicIPSupport(stack, 'PublicIPSupport', {
    cluster,
    service,
    dnsConfig: {
        domainName: 'www.example.com',
        hostzedZone: 'Z0000000000000000000X',
        assumedRole: 'arn:aws:iam::<the_other_account_id>:role/<the_role_name_to_assume>'
    },
})

In the target account you will need to define the role that this library can assume. You can create a role in the console to trust another AWS account. Then give it these permissions

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "route53:ChangeResourceRecordSets",
                "route53:ListResourceRecordSets"
            ],
            "Resource": [
                "arn:aws:route53:::hostedzone/Z0000000000000000000X"
            ]
        }
    ]
}

How it Works

This CDK Construct deploys an AWS Lambda and an Amazon EventBridge rule. The rule is defined to look for the lastStatus and desiredStatus attributes to be 'RUNNING' of an ECS Task State Change event. It is also specifically tied to the Service and Cluster passed into the constructor.

I was here

Note that I built this in my free time. This has nothing to do with my employer.

Enjoy! -Ray