# 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.
1. Choose the **Daemons** tab, then choose **Create**.
1. For **Daemon task definition family**, select your daemon task definition from the dropdown.
1. For **Daemon task definition revision**, select the revision to use. Leave blank to use the latest revision.
1. For **Daemon name**, enter a unique name. The name can contain up to 255 alphanumeric characters, hyphens, and underscores.
1. For **Capacity providers**, select one or more Amazon ECS Managed Instances capacity providers. These determine which instances run your daemon tasks.
1. (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`.
1. (Optional) Add tags.
1. (Optional) Turn on **Enable ECS Exec** to run interactive commands in your daemon containers for troubleshooting.
1. 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.
1. Choose the **Daemons** tab.
1. Verify that your daemon shows **Active** status.
1. 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.
1. Choose the **Daemons** tab, then select the daemon you want to update.
1. Choose **Update**.
1. For **Daemon task definition revision**, select the new revision.
1. (Optional) Update the capacity providers or deployment settings.
1. 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.
1. Choose the **Daemons** tab, then select the daemon you want to delete.
1. Choose **Delete**.
1. 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
```