# Deregistering an Amazon ECS external instance
<a name="ecs-anywhere-deregistration"></a>

We recommend that you deregister the instance from both Amazon ECS and AWS Systems Manager after you are done with the instance. Following deregistration, the external instance is no longer able to accept new tasks.

If you have tasks that are running on the container instance when you deregister it, the tasks remain running until they stop through some other means. However, these tasks are no longer monitored or accounted for by Amazon ECS. If these tasks on your external instance are part of an Amazon ECS service, then the service scheduler starts another copy of that task, on a different instance, if possible.

After you deregister the instance, clean up the remaining AWS resources on the instance. You can then register it to a new cluster.

## Procedure
<a name="ecs-anywhere-deregistration-procedure"></a>

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#### [ AWS Management Console ]

1. Open the console at [https://console.aws.amazon.com/ecs/v2](https://console.aws.amazon.com/ecs/v2).

1. From the navigation bar, choose the Region where your external instance is registered.

1. In the navigation pane, choose **Clusters** and select the cluster that hosts the external instance.

1. On the **Cluster : *name*** page, choose the **Infrastructure** tab.

1. Under **Container instances**, select the external instance ID to deregister. You're redirected to the container instance detail page.

1. On the **Container Instance : *id*** page, choose **Deregister**.

1. Review the deregistration message. Select **Deregister from AWS Systems Manager** to also deregister the external instance as an Systems Manager managed instance. Choose **Deregister**.
**Note**  
You can deregister the external instance as an Systems Manager managed instance in the Systems Manager console. For instructions, see [Deregistering managed nodes in a hybrid and multicloud environment](https://docs.aws.amazon.com/systems-manager/latest/userguide/fleet-manager-deregister-hybrid-nodes.html) in the *AWS Systems Manager User Guide*.

1. After you deregister the instance, clean up AWS resources on your on-premises server or VM.    
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-anywhere-deregistration.html)

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#### [ AWS CLI ]

1. You need the instance ID and the container instance ARN to deregister the container instance. If you do not have theses values, run the following comands

   Run the following commandto get the instance ID.

   You use the instance ID (`instanceID`) to get the container instance ARN (`containerInstanceARN`).

   ```
   instanceId=$(aws ssm describe-instance-information --region "{{ region }}" | jq ".InstanceInformationList[] |select(.IPAddress==\"{{ IPv4 Address }}\") | .InstanceId" | tr -d'"'
   ```

   Run the following commands.

   You use the `containerInstanceArn` as a parameter in the command to deregister the instance (`deregister-container-instance`).

   ```
   instances=$(aws ecs list-container-instances --cluster "{{ cluster }}" --region "{{ region }}" | jq -c '.containerInstanceArns')
   containerInstanceArn=$(aws ecs describe-container-instances --cluster "{{ cluster }}" --region "{{ region }}" --container-instances $instances | jq ".containerInstances[] | select(.ec2InstanceId==\"{{ instanceId }}\") | .containerInstanceArn" | tr -d '"')
   ```

1.  Run the following command to drain the instance.

   ```
   aws ecs update-container-instances-state --cluster "{{ cluster }}" --region "{{ region }}" --container-instances "{{ containerInstanceArn }}" --status DRAINING
   ```

1. After the container instance finishes draining, run the following command to deregister the instance.

   ```
   aws ecs deregister-container-instance --cluster "{{ cluster }}" --region "{{ region }}" --container-instance "{{ containerInstanceArn }}"
   ```

1. Run the following command to remove the container instance from SSM.

   ```
   aws ssm deregister-managed-instance --region "{{ region }}" --instance-id "{{ instanceId }}"
   ```

1. After you deregister the instance, clean up AWS resources on your on-premises server or VM.    
[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-anywhere-deregistration.html)

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