search(:node, "roles:hadoop-slavenode") do |nslave|
  # search(:node, "roles:hadoop-slavenode#{env_filter}") do |nslave|
  if !nslave[:fqdn].nil? && !nslave[:fqdn].empty?
    Chef::Log.info("HADOOP : SLAVE [#{nslave[:fqdn]}") if debug
    slave_nodes << nslave[:fqdn]