[AWS & Docker] Add ec2 instance to specific cluster

Background

By default, when we create a new ec2 instance, ecs will automatically assign that ec2 instance to the cluster named "default", but we want ecs to put it in an already created cluster.

How

When creating the ec2 instance, remember 3 major things

1. Select "ECS-optimized" instances in AMI community
2. Create IAM "ecsInstanceRole" to allow ecs have the right to run commands in ec2 instances
• Refer to https://docs.aws.amazon.com/AmazonECS/latest/developerguide/instance_IAM_role.html for more info
3. Configure "User Data" entry to let ecs know which cluster we want to place the ec2 instance to

#!/bin/bash
echo ECS_CLUSTER=[CLUSTER_NAME] >> /etc/ecs/ecs.config

References

• [AWS ECS] 將建立的 EC2 instance 加入指定的 Cluster
• Launching an Amazon ECS Container Instance Point (g)