task node

An EC2 instance that runs Hadoop map and reduce tasks, but does not store data. Task nodes are managed by the master node, which assigns Hadoop tasks to nodes and monitors their status. While a job flow is running you can increase and decrease the number of task nodes. Because they don't store data and can be added and removed from a job flow, you can use task nodes to manage the EC2 instance capacity your job flow uses, increasing capacity to handle peak loads and decreasing it later.

Task nodes only run a TaskTracker Hadoop daemon.