Question-46: What are the default permissions are granted to the user when created in LDAP or locally?

Answer: Ambari does not provide the default permissions when new user is created either locally or in LDAP.

Question-47: What is the use of Ambari agents?

Answer: In the Hadoop cluster there are 1000’s of nodes possible and each node needs to managed and monitored. For that Ambari require that agents are installed on each node in the cluster. And these installed agents can send the information about each node to the Ambari server. You can install Ambari agent manually on each node (this is not a good idea on the Big Cluster).

Question-48: Who creates the Unix accounts for each service user and groups?

Answer: Ambari is responsible for creating Unix accounts and for each service user and group during the cluster installations.

Question-49: Why do you need Unix account for each service?

Answer: Each Hadoop service runs under the ownership of their respective Unix accounts. These accounts are known as service users. And all these service users should be belonging to a Unix group. Usually user name are same as service name like Sqoop service would have Linux user name as sqoop. And for Slider it would be slider.

Question-50: Ambari uses the host name or IP to communicate with the agent installed on the hosts in the cluster?

Answer: Ambari Server need the host name of the Ambari agent to communicate and not the IP address. However, you can use the either private or custom host name.