To monitor Hadoop services from Cloudera Manager, log in to Cloudera Manager and navigate to the Home screen. The Home screen lists all the services configured within the cluster as shown in the following screenshot:
The status of the services can be in any of the following states:
Good Health: This is indicated by a green color
Concerning Health: This is indicated by an orange color
Bad Heath: This is indicated by a red color
The following are the steps to investigate a health issue for a service in a cluster. Let's try to identify the reason behind the Concerning Health status for the HDFS service.
Click on the Concerning Health (orange dot) status for the HDFS service. You should see the Health Tests section for the HDFS service as shown in the following screenshot:
As you can see in the preceding screenshot, the Health Tests section gives details about the concern. From the message, we now know that one of the four datanodes have a Concerning...