Final answer:
In the YARN/MRv2 framework, the ResourceManager daemon is responsible for arbitrating the execution of tasks among all applications, managing cluster resources and working with ApplicationMasters assigned to each application.
Step-by-step explanation:
Under the YARN/MRv2 framework, the daemon that arbitrates the execution of tasks among all the applications in the system is known as the ResourceManager. YARN, which stands for Yet Another Resource Negotiator is designed to manage and schedule the resources across a cluster in Hadoop. The ResourceManager is the master daemon and is responsible for allocating resources to various running applications while taking into account constraints such as capacity, queues and others.
It is important to note that although the ResourceManager allocates the resources the actual tracking and managing of the application's execution is done by another component called the ApplicationMaster. Each separate application running on the Hadoop cluster has its own instance of ApplicationMaster, which negotiates resources from the ResourceManager and works directly with the NodeManagers to execute and monitor tasks.