Associates a Greengrass service role with IoT Greengrass for your Amazon Web Services account in this Amazon Web Services Region. IoT Greengrass uses this role to verify the identity of client devices and manage core device connectivity information. The role must include the <a href="https://console.aws.amazon.com/iam/home#/policies/arn:awsiam::aws:policy/service-role/AWSGreengrassResourceAccessRolePolicy">AWSGreengrassResourceAccessRolePolicy</a> managed policy or a custom policy that defines equivalent permissions for the IoT Greengrass features that you use. For more information, see <a href="https://docs.aws.amazon.com/greengrass/v2/developerguide/greengrass-service-role.html">Greengrass service role</a> in the <i>IoT Greengrass Version 2 Developer Guide</i>.