Why 'mapred-site.xml' is not included in the latest Hadoop 2.2.0?
I believe it's still required. For our basic Hadoop 2.2.0 2-node cluster setup that we have working I did the following from the setup documentation.
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From the base of the Hadoop installation, edit the etc/hadoop/mapred-site.xml file. A new configuration option for Hadoop 2 is the capability to specify a framework name for MapReduce, setting the mapreduce.framework.name property. In this install we will use the value of "yarn" to tell MapReduce that it will run as a YARN application.First, copy the template file to the mapred-site.xml.
cp mapred-site.xml.template mapred-site.xml
Next, copy the following into Hadoop etc/hadoop/mapred-site.xml file and remove the original empty tags.
<configuration> <property> <name>mapreduce.framework.name</name> <value>yarn</value> </property> </configuration>"
Wrt documentation, I found this the most useful. Also, etc/hosts configs for cluster setup and other cluster related configs were a bit hard to figure out.