title: Load balancer health check vs docker health check?
body: <p>I have an ECS cluster with multiple nodes (task defs) fronted by an application load balancer. Does it make sense to configure a health check at the load balancer and at the container level (within the task definition)?</p>
  <p>The load balancer runs the configured health check against <a href="https://docs.aws.amazon.com/elasticloadbalancing/latest/application/target-group-health-checks.html" rel="nofollow noreferrer">every registered target</a> so it can unregister failing nodes. Setting the health check at the container level accomplishes the same thing: ECS will unregister any container that fails the health check (according to your configuration). ECS will always instantiate more instances of your task def to satisfy your desired count.</p>
  <p>To me it sounds like if your task definition only has a single container, then only setting the health check at the load balancer (since it's required) is enough. Am I missing anything?</p>