Cluster Management - Big Data Made Easy: A Working Guide to the Complete Hadoop Toolset - page 237

After I click Continue, the manager carries out a host inspection to determine whether there are any problems
with the server. If there are none, I click Finish to advance to the first page of the cluster setup, as shown in Figure 8-14 ,
where I then choose the CDH services to be installed. I choose to install Core Hadoop to reduce the load on my servers,
then click Continue.
Figure 8-14. CDH service installation
Next, I assign the roles that determine where the services will run. For instance, I remember that ZooKeeper
needs a quorum of instances and that it must be an odd number of instances so they can vote successfully. Figure 8-15
shows my assignments. I then click Continue.