Checking stopped tasks for errors

If you have trouble starting a task, your task might be stopping because of an error. For example, you run the task and the task displays a PENDING status and then disappears. You can view stopped task errors like this in the Amazon ECS console by viewing the stopped task and inspecting it for error messages.

Important

Amazon ECS also sends task state change events to EventBridge which you can view if your stopped task has expired from view in the Amazon ECS console. For more information, see Task state change events.

To check stopped tasks for errors (AWS Management Console)

1. Open the Amazon ECS console at https://console.aws.amazon.com/ecs/.

2. On the Clusters page, select the cluster in which your stopped task resides.

3. On the Cluster : clustername page, choose Tasks.

4. In the Desired task status table header, choose Stopped, and then select the stopped task to inspect. The most recent stopped tasks are listed first.

5. In the Details section, inspect the Stopped reason field to see the reason that the task was stopped.

   

   Some possible reasons and their explanations are listed below:

   Task failed ELB health checks in (elb elb-name)

   The current task failed the Elastic Load Balancing health check for the load balancer that is associated with the task's service. For more information, see Troubleshooting service load balancers.

   Scaling activity initiated by (deployment deployment-id)

   When you reduce the desired count of a stable service, some tasks must be stopped in order to reach the desired number. Tasks that are stopped by downscaling services have this stopped reason.

   Host EC2 (instance id) stopped/terminated

   If you stop or terminate a container instance with running tasks, then the tasks are given this stopped reason.

   Container instance deregistration forced by user

   If you force the deregistration of a container instance with running tasks, then the tasks are given this stopped reason.

   Essential container in task exited

   If a container marked as essential in task definitions exits or dies, that can cause a task to stop. When an essential container exiting is the cause of a stopped task, the Step 6 can provide more diagnostic information as to why the container stopped.

6. If you have a container that has stopped, expand the container and inspect the Status reason row to see what caused the task state to change.

   

   In the previous example, the container image name cannot be found. This can happen if you misspell the image name.

   If this inspection does not provide enough information, you can connect to the container instance with SSH and inspect the Docker container locally. For more information, see Inspect Docker Containers.

To check stopped tasks for errors (AWS CLI)

1. List the stopped tasks in a cluster. The output will contain the Amazon Resource Name (ARN) of the task, which you need to describe the task.

   aws ecs list-tasks \
        --cluster cluster_name \
        --desired-status STOPPED \
        --region us-west-2

2. Describe the stopped task to retrieve the stoppedReason in the response.

   aws ecs describe-tasks \
        --cluster cluster_name \
        --tasks arn:aws:ecs:us-west-2:account_id:task/cluster_name/task_ID \
        --region us-west-2