RSAT tools can be installed using the built-in Windows DISM tool. As an example, run the following command in an elevated command prompt to install the RSAT Group Policy Management Tools, RSAT Active Directory Domain Services and Lightweight Directory Services Tools and RSAT DNS Server Tools.

dism /online /add-capability /CapabilityName:Rsat.GroupPolicy.Management.Tools~~~~0.0.1.0 /CapabilityName:Rsat.Dns.Tools~~~~0.0.1.0 /CapabilityName:Rsat.ActiveDirectory.DS-LDS.Tools~~~~0.0.1.0