Question-126: What is Cloudera Management Service?

Answer: Using Cloudera Management Service various management features are implemented for example below

• Activity Monitor-Collects information about activities run by the MapReduce service.
• Host Monitor-Collect health and matric information about the Host.
• Service Monitor-Collects health and metric information about services and activity information from the YARN and Impala services.
• Event server-Aggregates relevant Hadoop events and makes them available for alerting and searching.
• Alerts: Generates and delivers the alerts for certain types of events.
• Report Manager: Reports for Historical view.

Cloudera Management service manages each role separately, instead of as part of the Cloudera Manager server. 

Question-127: In Cloudera Cluster, how service and roles are related?

Answer: Whenever you configure a service for the Cloudera Manager then it allocates the various possible roles like HDFS, this is one service and under which there are various roles like NameNode, SecondaryNameNode, DataNode etc. 

• One host would run NameNode Role
• One host would run the Secondary NameNode role
• Another Host would run the Balancer Role
• Remaining Hosts run DataNode roles. 

Question-128: What is Role Group?

Answer: A role group is a set of configuration properties for a role type, as well as of role instances associated with that Group. Cloudera Manager automatically creates a default role group named Role Type Default Group for each role type. 

Question-129: What is Client Configuration Files?

Answer: To unlock client to use the HBase, Hive, MapReduce, YARN, MapReduce etc. Cloudera manager creates zip archive after configuration files containing the service properties, and this zip archive is referred as a client configuration file. Each archive contains the set of configuration files needed to access the service for example the MapReduce client configuration file contains copies of

• core-site.xml
• hadoop-env.sh
• hdfs-site.xml
• log4j.properties
• Mapred-site.xml

Clint configuration files are generated automatically by Cloudera manager based on the services and Roles you have installed and Cloudera Manager deploys these configurations automatically when you install your cluster, add a service on a host or at a Gateway Role on a host. 

Question-130: How the client configuration is deployed?

Answer:  Client configuration files are deployed on any host that is a client for a service.  For example, Data node client configuration installed on the same node where the data node role is installed.  however, you can use this client configuration on another host as well. Cloudera manager will deploy client configuration files automatically in many cases, if you have modified the configuration for a service, then you need to redeploy those configuration file.