serviceRoleArn

The Amazon Resource Name (ARN) of the IAM service role for Amazon Web Services Systems Manager to assume when running a maintenance window task. If you do not specify a service role ARN, Systems Manager uses a service-linked role in your account. If no appropriate service-linked role for Systems Manager exists in your account, it is created when you run RegisterTaskWithMaintenanceWindow.

However, for an improved security posture, we strongly recommend creating a custom policy and custom service role for running your maintenance window tasks. The policy can be crafted to provide only the permissions needed for your particular maintenance window tasks. For more information, see Setting up Maintenance Windows in the in the Amazon Web Services Systems Manager User Guide.