Detect server name in PHP

I have a number of instances behind a loadbalancer. Is it possible to detect the name of the machine (e.g. ec2-XXX-XX-XXX-XXX.compute-1.amazonaws.com) in PHP for debugging? I looked through phpinfo() and it doesn't seem to have any kind of machine specific information.

From serverfault Louis W

• This should do it:

  http://php.net/manual/en/reserved.variables.server.php

  $myservername = $_SERVER['SERVER_NAME'];
  

  Louis W : $_SERVER['SERVER_NAME'] is set to the domain name of my website, not the machine name. Because these are load balanced cloud instances I am sure there is a lot of magic happening behind the scenes.
  From Force Flow

• you'll have to use $host = system("hostname") or similar as it appears PHP won't provide that info directly.

  IP seems a little more involved. Depends on how they've got things set up but you can try

  $config = system("ifconfig | grep \"inet addr\"");
  preg_match("/(\d{1,3})(\.\d{1,3})/", $config, $matches);
  $ip_addr = $matches[1];
  

  Louis W : Hmmm. I think we are getting closer, but all machines are reporting 'p-aws-img-www-02' as the hostname.

  Louis W : Is there a way to get the machine's (not the domain's) ip address?
  From bemace