How can I connect my autoscaling group to my ecs cluster?

Question

In all tutorials for ECS you need to create a cluster and after that an autoscaling group, that will spawn instances. Somehow in all these tutorials the instances magically show

Answer 1

Well, i found out. Its all about the ecs-agent and its config file /etc/ecs/ecs.config (This file will be created through the Userdata field, when creating EC2 instances, even from an autoscaling configuration.) Read about its configuration options here: http://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-agent-config.html

But you can even copy a ecs.config stored on Amazon S3, do it like this (following lines go into Userdata field):

#!/bin/bash
yum install -y aws-cli
aws configure set default.s3.signature_version s3v4
aws configure set default.s3.addressing_style path
aws configure set default.region eu-central-1
aws s3 cp s3:///ecs.config /etc/ecs/ecs.config

note: Signature_version v4 is specific for some regions, like eu-central-1. This ofc only works, if your IAM role for the instance (in my case its ecsInstanceRole) has the right AmazonS3ReadOnlyAccess

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The AWS GUI console way for that would be: Use the cluster wizard at https://console.aws.amazon.com/ecs/home#/firstRun . It will create an autoscaling grou for your cluster, a loadbalancer in front of it, and connect it all nicely.