qualified domain name (FQDN) of a Pod is set as hostname of its containers. 
  In Linux containers, this means setting the FQDN in the hostname field of the 
  kernel (the nodename field of struct utsname).  In Windows containers, this
  means setting the this means setting the registry value of hostname for the registry key HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters to FQDN.