Automatic public DNS for Fargate-managed containers in Amazon ECS

Fargate-managed containers in ECS lack build-in support for registering services into public DNS namespaces (12/2018). This is an event-driven approach to automatically register the public IP of a deployed container in a Route 53 hosted zone.

See this blog post for more information.

How it works

A lambda function subscribes to an "ECS Task State Change" event. It gets called whenever a container has started up. What the function does is :

• fetching the public IP from the container
• construct a subdomain for the container
• register the public IP for the subdomain in Route 53

Installation

First you need to pull NodeJs dependencies using:

npm install

You need to have the Serverless Framework CLI installed.

Deploy the function in your active AWS account:

serverless deploy

In your ECS console, select your cluster and add the tags

• hostedZoneId (the hosted zone id of your public DNS namespace, for example Z1OAI7EUAR14MP)
• domain (the domain name of your public DNS namespace, for example foby.org)

Demo

Well, just start a Fargate task in your cluster. When the task has started up, the function creates an A-record-set in your hosted zone with the containers' service name as subdomain.