private static void SetPreferredDC(string domainController)
{
string dnsHostName = DirectoryUtilities.PickGlobalCatalog(domainController).DnsHostName;
SetupServerSettings setupServerSettings = SetupServerSettings.CreateSetupServerSettings();
setupServerSettings.SetConfigurationDomainController(TopologyProvider.LocalForestFqdn, new Fqdn(domainController));
setupServerSettings.SetPreferredGlobalCatalog(TopologyProvider.LocalForestFqdn, new Fqdn(dnsHostName));
setupServerSettings.AddPreferredDC(new Fqdn(domainController));
ADSessionSettings.SetProcessADContext(new ADDriverContext(setupServerSettings, ContextMode.Setup));
}