anchor.diff:  In a managed domain, the XML files are found in the
   `domain/configuration` directory. There are two types of configuration
   files – one per host, and then a single domain-wide file managed by the
  -master host, aka the Domain Controller. (For more on the types of
  +primary Host Controller, aka the Domain Controller. (For more on the types of
   processes in a managed domain, see <<Operating_modes,Operating
   Modes>>.)
   
  
positive.code: ==== Domain Wide Configuration – domain.xml
  
  Once a Host Controller has processed its host-specific configuration, it
  knows whether it is configured to act as the master Domain Controller.
  If it is, it must parse the domain wide configuration file, by default
  located at `domain/configuration/domain.xml`. This file contains the
  bulk of the settings that should be applied to the servers in the domain
  
negative.code: ----
  
  That argument is only relevant for hosts configured to act as the
  Domain Controller.
  
  A secondary Host Controller does not usually parse the domain wide
  configuration file. A secondary Host Controller gets the domain wide configuration from the
  remote Domain Controller when it registers with it. A secondary Host Controller also
  will not persist changes to a `domain.xml` file if one is present on the
  filesystem. For that reason it is recommended that no `domain.xml` be
  kept on the filesystem of hosts that will only run as secondary Host Controllers.
  
  A secondary Host Controller can be configured to keep a locally persisted copy of the domain
  wide configuration and then use it on boot (in case the Domain Controller is not
  available.) See _--backup and --cached-dc_ under
  <<Command_line_parameters,Command line parameters>>.
  