`deployment` Map
The deployment section contains parameters to control how many tasks run during the deployment and the ordering of stopping and starting tasks.
deployment.`rolling` String
Rolling deployment strategy. Valid values are
- `"default"`: Creates new tasks as many as the desired count with the updated task definition, before stopping the old tasks. Under the hood, this translates to setting the [`minimumHealthyPercent`](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service_definition_parameters.html#minimumHealthyPercent) to 100 and [`maximumPercent`](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service_definition_parameters.html#maximumPercent) to 200.
- `"recreate"`: Stop all running tasks and then spin up new tasks. Under the hood, this translates to setting the [`minimumHealthyPercent`](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service_definition_parameters.html#minimumHealthyPercent) to 0 and [`maximumPercent`](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service_definition_parameters.html#maximumPercent) to 100.
deployment.`rollback_alarms` Array of Strings or Map
!!! info
If an alarm is in "In alarm" state at the beginning of a deployment, Amazon ECS will NOT monitor alarms for the duration of that deployment. For more details, read the docs [here](https://docs.aws.amazon.com/AmazonECS/latest/userguide/deployment-alarm-failure.html).
As a list of strings, the names of existing CloudWatch alarms to associate with your service that may trigger a [deployment rollback](https://docs.aws.amazon.com/AmazonECS/latest/userguide/deployment-alarm-failure.html).
```yaml
deployment:
rollback_alarms: ["MyAlarm-ELB-4xx", "MyAlarm-ELB-5xx"]
```
As a map, the alarm metric and threshold for Copilot-created alarms.
Available metrics: