Creating and managing daemons - Amazon Elastic Container Service
PrerequisitesCreating a daemonVerifying daemon deploymentUpdating a daemonDeleting a daemon

Creating and managing daemons

After you register a daemon task definition, create a daemon to deploy it across your Amazon ECS Managed Instances capacity providers. Amazon ECS automatically places one daemon task on every Amazon EC2 instance in the associated capacity providers and manages the daemon lifecycle.

Prerequisites

Before you create a daemon, verify that you have the following:

  • An Amazon ECS cluster.

  • One or more Amazon ECS Managed Instances capacity providers associated with the cluster.

  • A registered daemon task definition.

Creating a daemon

AWS Management Console

  1. Open the Amazon ECS console. In the left navigation, choose Clusters, then select your cluster.

  2. Choose the Daemons tab, then choose Create.

  3. For Daemon task definition family, select your daemon task definition from the dropdown.

  4. For Daemon task definition revision, select the revision to use. Leave blank to use the latest revision.

  5. For Daemon name, enter a unique name. The name can contain up to 255 alphanumeric characters, hyphens, and underscores.

  6. For Capacity providers, select one or more Amazon ECS Managed Instances capacity providers. These determine which instances run your daemon tasks.

  7. (Optional) Configure deployment settings:

    • Drain percentage - Percentage of instances to drain simultaneously during updates. Default: 25.

    • Use CloudWatch alarm(s) - Turn on to monitor deployment health and automatically roll back if alarms trigger.

    • Bake time - The number of minutes that Amazon ECS waits after it updates all instances to the new daemon revision before it completes the deployment. During this period, Amazon ECS monitors CloudWatch alarms and automatically rolls back the deployment if any alarm triggers. Default: 0.

  8. (Optional) Add tags.

  9. (Optional) Turn on Enable ECS Exec to run interactive commands in your daemon containers for troubleshooting.

  10. Review your configuration and choose Create.

AWS CLI

Create a JSON file with your daemon configuration and run the create-daemon command.

The following is an example JSON file:

{
    "clusterArn": "arn:aws:ecs:us-east-1:123456789012:cluster/my-daemon-cluster",
    "daemonName": "my-monitoring-daemon",
    "daemonTaskDefinitionArn": "arn:aws:ecs:us-east-1:123456789012:daemon-task-definition/my-daemon-task:1",
    "capacityProviderArns": [
        "arn:aws:ecs:us-east-1:123456789012:capacity-provider/my-daemon-capacity-provider"
    ]
}

Run the following command to create the daemon:

aws ecs create-daemon --cli-input-json file://create-daemon.json

Required fields

  • daemonName - A unique name for the daemon.

  • clusterArn - The ARN of the cluster.

  • daemonTaskDefinitionArn - The ARN of the daemon task definition.

  • capacityProviderArns - An array of Amazon ECS Managed Instances capacity provider ARNs.

Optional fields

  • deploymentConfiguration - A DaemonDeploymentConfiguration object to customize deployment behavior.

  • tags - Key-value pairs for tagging.

  • propagateTags - Tag propagation setting.

  • clientToken - An idempotency token.

Verifying daemon deployment

After you create a daemon, verify its status by using the AWS Management Console or the AWS CLI.

AWS Management Console

  1. Open the Amazon ECS console. In the left navigation, choose Clusters, then select your cluster.

  2. Choose the Daemons tab.

  3. Verify that your daemon shows Active status.

  4. Choose the Tasks tab to confirm that one daemon task runs on each container instance.

AWS CLI

Run the following commands to verify daemon status:

aws ecs list-daemons \
    --cluster-arn arn:aws:ecs:us-east-1:123456789012:cluster/my-daemon-cluster
aws ecs describe-daemons \
    --daemon-arn arn:aws:ecs:us-east-1:123456789012:daemon/my-daemon-cluster/my-monitoring-daemon

Updating a daemon

To update a daemon with a new task definition revision or to add capacity providers, use the AWS Management Console or the AWS CLI. This triggers a rolling deployment across all instances.

AWS Management Console

  1. Open the Amazon ECS console. In the left navigation, choose Clusters, then select your cluster.

  2. Choose the Daemons tab, then select the daemon you want to update.

  3. Choose Update.

  4. For Daemon task definition revision, select the new revision.

  5. (Optional) Update the capacity providers or deployment settings.

  6. Choose Update to start the rolling deployment.

AWS CLI

Run the update-daemon command:

aws ecs update-daemon \
    --daemon-arn arn:aws:ecs:us-east-1:123456789012:daemon/my-daemon-cluster/my-monitoring-daemon \
    --daemon-task-definition-arn arn:aws:ecs:us-east-1:123456789012:daemon-task-definition/my-daemon-task:2 \
    --capacity-provider-arns arn:aws:ecs:us-east-1:123456789012:capacity-provider/my-daemon-capacity-provider
Important

When you provide daemon configuration settings in an UpdateDaemon request, Amazon ECS uses your specified settings instead of the defaults. Daemon configuration settings, including tags and the enable execute command flag, are not persisted between updates. Each call to UpdateDaemon must include the full set of configuration settings you want applied. Any settings omitted from the request revert to their default values.

Deleting a daemon

To delete a daemon, use the AWS Management Console or the AWS CLI. Wait for all daemon tasks to stop before you delete the capacity provider or cluster.

AWS Management Console

  1. Open the Amazon ECS console. In the left navigation, choose Clusters, then select your cluster.

  2. Choose the Daemons tab, then select the daemon you want to delete.

  3. Choose Delete.

  4. In the confirmation dialog, choose Delete to confirm.

AWS CLI

Run the delete-daemon command:

aws ecs delete-daemon \
    --daemon-arn arn:aws:ecs:us-east-1:123456789012:daemon/my-daemon-cluster/my-monitoring-daemon