I have two Datanodes (no other component on them except datanode and nodemanagers) and a master node (a higher config machine) containing the YARN/HDFS and other master components. I want to set up an alert for the CPU utilization of the Datanodes, which as I've mentioned do not have any other components).
Currently there is no In-built Host CPU alert available in Ambari.
But ambari allows you to create your own alerts based on your specific requierment and then register it.
I have written a similar article here (for host disk space alerting), May be you would like to take a look at it.
I have attached the complete Zip with the Testcase in the same Article link that i posted earlier. It can also be downloaded from.