# YARN: Exec Modes

## How to execute tasks?

* **Local mode**
  * Job is submitted on the (master) node of the Resource Manager
* **Remote**
  * Hadoop is installed on a remote machine
  * Hadoop client jars installed on the local computer
  * Hadoop configuration files define the remote Hadoop cluster for the local Hadoop client
  * *Does not work for few cases*
* **SCP + remote**
  * SCP + SSH + run locally

## WRITING CUSTOM APPLICATIONS

Grand total of 3 protocols:

* ApplicationClientProtocol
  * Application launching program
  * submitApplication
* ApplicationMasterProtocol
  * Protocol between AM & RM for resource allocation
  * registerApplicationMaster / allocate / finishApplicationMaster
* ContainerManagementProtocol
  * Protocol between AM & NM for container start/stop
  * startContainers / stopContainers