It is the same as all other communication in Hadoop: Hadoop RPC which in turn is java RPC over a TPC connection.

+Vinod Kumar Vavilapalli
Hortonworks Inc.

On Apr 22, 2013, at 8:27 AM, Rahul Bhattacharjee wrote:


Tasktracer runs each of the tasks (M or R) in a separate VM (considering VM reuse is disabled).So the actual task and task tracer daemon run in two different OS processes. Umbilical interface is used by tasks to send its progress to the task tracer.

Considering that both are different process then how is the umbilical interface implemented ? shared file , sockets (unlikely) or ..