I've setup a Hadoop 2.2 cluster with 1 master node(namenode and secondary namenode) and 3 slave nodes(datanode and namenode on each one).All of the machines use Linux Mint 64bit. When I run my MapReduce program, writen in Java, I can only see that master node is using extra CPU and RAM. Slave nodes are not doing a thing. I've checked the logs from all of the namenodes and there is nothing wrong with the namenodes on slave nodes. Resource Manager is running and all of the slave nodes can see the Resource Manager. I used this http://n0where.net/hadoop-2-2-multi-node-cluster-setup/ tutorial to configure my nodes. Datanodes are working in terms of distributed data storing but I can't see any indication of distributed data processing. Do I have to configure the xml configuration files in some other way so all of the machines will process data while I'm running my MapReduce Job?