DSC Configuration script to add a replica DC to an existing Active Directory Domain

CreateADReplicaDC.ps1

Configuration CreateADReplicaDC 
{ 
   param 
    ( 
        [Parameter(Mandatory)][String]$DomainName,
        [Parameter(Mandatory)]
        [System.Management.Automation.PSCredential]$Admincreds,
        [Parameter(Mandatory)]
        [System.Management.Automation.PSCredential]$SafemodeAdminCreds,
        [Int]$RetryCount=20,
        [Int]$RetryIntervalSec=30
    )
    Import-DscResource -ModuleName xActiveDirectory, xPendingReboot
    [System.Management.Automation.PSCredential]$DomainCreds = New-Object System.Management.Automation.PSCredential ("${DomainName}\$($Admincreds.UserName)", $Admincreds.Password)

    Node localhost
    {
       LocalConfigurationManager            
       {            
          ActionAfterReboot = 'ContinueConfiguration'            
          ConfigurationMode = 'ApplyOnly'            
          RebootNodeIfNeeded = $true            
       }

       WindowsFeature RSAT 
       {
          Ensure = "Present"
          Name = "RSAT"
       }

       WindowsFeature ADDSInstall 
       { 
          Ensure = "Present" 
          Name = "AD-Domain-Services"
       }

       xWaitForADDomain DscForestWait 
       { 
          DomainName = $DomainName 
          DomainUserCredential= $DomainCreds
          RetryCount = $RetryCount
          RetryIntervalSec = $RetryIntervalSec
          DependsOn = "[WindowsFeature]ADDSInstall"
      }

      xADDomainController ReplicaDC 
      { 
         DomainName = $DomainName 
         DomainAdministratorCredential = $DomainCreds 
         SafemodeAdministratorPassword = $SafeModeAdminCreds
         DatabasePath = "C:\NTDS"
         LogPath = "C:\NTDS"
         SysvolPath = "C:\SYSVOL"
         DependsOn = "[xWaitForADDomain]DScForestWait"
      }

      xPendingReboot Reboot1
      { 
         Name = "RebootServer"
         DependsOn = "[xADDomainController]ReplicaDC"
      }
   }
}