The general concept of apche hadoop is that an Application Submission Client submits an Application to the YARN Resource Manager. The client communicates with the resourcemanager using the ApplicationClientProtocol to first acquires a new ApplicationId. if its require via ApplicationClientProtocol#getNewApplication and after that submits the Application to be run via ApplicationClientProtocol#submit Application. As one of the part of ApplicationClientProtocol#submitApplication call, the cliets provides sufficient information to ResourceManager to launch the made application first container thats mean ApplicationMaster. You need to provide information like as the details about the local files and jar files that needs to be available for your application to run your application, the actual command that needs to be execute . Any Unix environment settings. Effectively, you have to describe the Unix process that needs to be launched for your Applicationmaster.
educba