Launch ECS container instance to cluster and run task definition using userdata

Question

I am trying to launch an ECS contianer instance and passing through userdata to register it to a cluster and also start run a task definition.

When the task is complete the instance will be terminated.

I am using the guide on AWS docs to start a task at container launch. Below userdata(cluster and task def params omitted)

Content-Type: multipart/mixed; boundary="==BOUNDARY=="
MIME-Version: 1.0

--==BOUNDARY==
Content-Type: text/x-shellscript; charset="us-ascii"

#!/bin/bash
# Specify the cluster that the container instance should register into
cluster=my_cluster

# Write the cluster configuration variable to the ecs.config file
# (add any other configuration variables here also)
echo ECS_CLUSTER=$cluster >> /etc/ecs/ecs.config

# Install the AWS CLI and the jq JSON parser
yum install -y aws-cli jq

--==BOUNDARY==
Content-Type: text/upstart-job; charset="us-ascii"

#upstart-job
description "Amazon EC2 Container Service (start task on instance boot)"
author "Amazon Web Services"
start on started ecs

script
    exec 2>>/var/log/ecs/ecs-start-task.log
    set -x
    until curl -s http://localhost:51678/v1/metadata
    do
        sleep 1
    done

    # Grab the container instance ARN and AWS region from instance metadata
    instance_arn=$(curl -s http://localhost:51678/v1/metadata | jq -r '. | .ContainerInstanceArn' | awk -F/ '{print $NF}' )
    cluster=$(curl -s http://localhost:51678/v1/metadata | jq -r '. | .Cluster' | awk -F/ '{print $NF}' )
    region=$(curl -s http://localhost:51678/v1/metadata | jq -r '. | .ContainerInstanceArn' | awk -F: '{print $4}')

    # Specify the task definition to run at launch
    task_definition=my_task_def

    # Run the AWS CLI start-task command to start your task on this container instance
    aws ecs start-task --cluster $cluster --task-definition $task_definition --container-instances $instance_arn --started-by $instance_arn --region $region
end script
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When the instance is created it is launched to the default cluster not the one I specify in the userdata and no tasks are started.

I have deconstructed the above script to work out where it is failing but Ive had no luck.

Any help would be appreciated.

Answer 1

From the AWS Documentation .

Configure your Amazon ECS container instance with user data, such as the agent environment variables from Amazon ECS Container Agent Configuration. Amazon EC2 user data scripts are executed only one time, when the instance is first launched.

By default, your container instance launches into your default cluster. To launch into a non-default cluster, choose the Advanced Details list. Then, paste the following script into the User data field, replacing your_cluster_name with the name of your cluster.

So, in order for you to be able to add that EC2 instance to your ECS cluster, You should change this variable to the name of your cluster:

# Specify the cluster that the container instance should register into
cluster=your_cluster_name

Change your_cluster_name to whatever the name is of your cluster.