What is the difference between managed and unmanaged application manager in YARN

Question

I am experimenting with the Distributed Shell example in YARN 2.2 and hope someone can clarify what is the difference between a managed and non-managed application manager?

For example, the following lines are displayed in client code

// unmanaged AM appContext.setUnmanagedAM(true); 

but I cannot find the documentation explaining the difference that this line affects the execution behavior.

Many thanks.

Answer 1

setUnmanagedAM(true) used for debugging purposes, that is, it launches the application manager in local mode and does not send it to the cluster, so it’s easier to enter the code and debug it. You can see it in using hadoop-yarn-applications-unmanaged-am-launcher.jar that comes with yarn