@augeas { '/etc/hadoop/conf/mapred-site.xml':
      lens => 'xml.lns',
      incl => '/etc/hadoop/conf/mapred-site.xml',
      changes => [
  "set configuration/property[name/#text = 'mapreduce.map.java.opts']/name/#text mapreduce.map.java.opts",
  "set configuration/property[name/#text = 'mapreduce.map.java.opts']/value/#text -Xmx${mapmem}m",

  "set configuration/property[name/#text = 'mapreduce.reduce.java.opts']/name/#text mapreduce.reduce.java.opts",
  "set configuration/property[name/#text = 'mapreduce.reduce.java.opts']/value/#text -Xmx${reducemem}m",

  "set configuration/property[name/#text = 'mapreduce.job.maps']/name/#text mapreduce.job.maps",
  "set configuration/property[name/#text = 'mapreduce.job.maps']/value/#text ${maps}",

  "set configuration/property[name/#text = 'mapreduce.map.memory.mb']/name/#text mapreduce.map.memory.mb",
  "set configuration/property[name/#text = 'mapreduce.map.memory.mb']/value/#text ${mapmem}",

  "set configuration/property[name/#text = 'mapreduce.job.reduces']/name/#text mapreduce.job.reduces",
  "set configuration/property[name/#text = 'mapreduce.job.reduces']/value/#text ${reduces}",

  "set configuration/property[name/#text = 'yarn.app.mapreduce.am.command-opts']/name/#text yarn.app.mapreduce.am.command-opts",
  "set configuration/property[name/#text = 'yarn.app.mapreduce.am.command-opts']/value/#text -Xmx${reducemem}m",

  "set configuration/property[name/#text = 'yarn.app.mapreduce.am.command-opts']/name/#text yarn.app.mapreduce.am.command-opts",
  "set configuration/property[name/#text = 'yarn.app.mapreduce.am.command-opts']/value/#text -Xmx${reducemem}m",

  "set configuration/property[name/#text = 'mapreduce.reduce.memory.mb']/name/#text mapreduce.reduce.memory.mb",
  "set configuration/property[name/#text = 'mapreduce.reduce.memory.mb']/value/#text ${reducemem}",

  # handy bit of template for search/replace the key and values
  #"set configuration/property[name/#text = 'K']/name/#text K",
  #"set configuration/property[name/#text = 'K']/value/#text V",
      ],
    }
    Augeas<| title == '/etc/hadoop/conf/mapred-site.xml' |>