title: Missing container attribute
body: <p>I am running EC2 instance with RancherOS ECS-enabled AMI v1.0.4 in ECS cluster.</p>
  
  <p>The instance joins cluster, but ECS tasks are failing to start because container instance is missing an attribute required by the task.</p>
  
  <p>The ECS task that is failing to start has IAM role and requires <code>com.amazonaws.ecs.capability.task-iam-role</code> attribute. After checking which attributes the container instance has (using cli aws ecs describe-container-instances), it can be seen that this required attribute is missing.</p>
  
  <p>When I remove IAM role from the task, it starts fine.</p>
  
  <p>When I run instance with Amazon ECS-optimized AMI everything works fine.</p>
  
  <p>I followed <a href="http://rancher.com/docs/os/v1.0/en/amazon-ecs/" rel="nofollow noreferrer">official RancherOS ECS guide</a>, including verifying ECS Container Instance IAM Role, without success.</p>