hadoop2.2.0 core-site.xml--Rack Configuration

<!-- Rack Configuration -->

<property>
    <name>net.topology.node.switch.mapping.impl</name>
  <value>org.apache.hadoop.net.ScriptBasedMapping</value>
  <description> The default implementation of the DNSToSwitchMapping. It
    invokes a script specified in net.topology.script.file.name to resolve
    node names. If the value for net.topology.script.file.name is not set, the
    default value of DEFAULT_RACK is returned for all node names.
  </description>
</property>

注释：

<property>
  <name>net.topology.script.file.name</name>
  <value></value>
  <description> The script name that should be invoked to resolve DNS names to
    NetworkTopology names. Example: the script would take host.foo.bar as an
    argument, and return /rack1 as the output.
  </description>
</property>

注释：

<property>
  <name>net.topology.script.number.args</name>
  <value>100</value>
  <description> The max number of args that the script configured with 
    net.topology.script.file.name should be run with. Each arg is an
    IP address.
  </description>
</property>

注释：