redis health replication role check for the ELB

redistest.php

<?php
// redis test
$r = new Redis();
$r->connect('127.0.0.1', 6379, 2.5); // connect to redis with 2.5 sec timeout
if(!$r) {
  header('HTTP/1.1 500 Internal Server Error');
  echo "Error: connection failed\n";
  exit(0);
}

$repl=$r->info("replication");
if($repl["role"] == "master") {
  echo "Redis is ready\n";
  exit(0);
}
else {
  header('HTTP/1.1 501 Internal Server Error');
  echo "Server role is:".$repl["role"]."\n";
  exit (0);
}

?>