This document outlines the key tasks and responsibilities of a Hadoop administrator. It discusses five top Hadoop admin tasks: 1) cluster planning which involves sizing hardware requirements, 2) setting up a fully distributed Hadoop cluster, 3) adding or removing nodes from the cluster, 4) upgrading Hadoop versions, and 5) providing high availability to the cluster. It provides guidance on hardware sizing, installing and configuring Hadoop daemons, and demos of setting up a cluster, adding nodes, and enabling high availability using NameNode redundancy. The goal is to help administrators understand how to plan, deploy, and manage Hadoop clusters effectively.