Using Service-Linked Roles for Migration Hub
AWS Migration Hub uses AWS Identity and Access Management (IAM) service-linked roles. A service-linked role is a unique type of IAM role that is linked directly to Migration Hub. Service-linked roles are predefined by Migration Hub and include all the permissions that the service requires to call other AWS services on your behalf.
A service-linked role makes setting up Migration Hub easier because you don't have to manually add the necessary permissions. Migration Hub defines the permissions of its service-linked roles, and the services that can assume its roles. The permissions include the trust policy and the permissions policy, which cannot be attached to any other IAM entity.
For information about other services that support service-linked roles, see AWS Services That Work with IAM and look for the services that have Yes in the Service-Linked Role column. Choose a Yes with a link to view the service-linked role documentation for that service.