To start with we have just installed few services like HDFS, YARN, and zookeeper in our CDH setup. The Cloudera Manager enables you to add any other service later on. As a part of the exam, you may be asked to add a new service to the CDH cluster. The process remains fairly simple for all the services. I have deleted the YARN service and will outline the steps to add the service below.
Adding a new service (YARN) using Cloudera Manager
1. From the Cloudera Manager home page, select the option “Add Service” under Cluster operations drop-down.
2. This will open an Add Service Wizard which will guide us through the rest of the procedure. The page will list of available services for addition.
Let’s select the YARN service to add to our cluster.
3. Next, we have to customize the role assignments for YARN. Here, you can select which role is to be assigned to which node in the CDH cluster.
4. You can review the changes on the next pages. You can also edit the configuration parameters on this page if you want. I will be keeping the default parameter values intact and continue with the installation.
As shown in the screenshot, the installation finished without any error or warnings.
You should also get a congratulations screen as shown below.
5. Verify if the service is running error free on the Cloudera Manager Home Page.
Customizing Roles assignments in the exam
When you add any new service it would have different roles associated with it. In the exam, you would probably be given specific hosts for role assignments. In case if the role assignment is not given, you need not assign a role to any host. For example, in the case of Kafka service, you may be asked only to assign the role “Kafka Broker” to a specific host. But the other 2 roles “Kafka MirrorMaker” and “gateway” may not have been specifically asked to assign to any host. In that case, we can leave the last 2 roles unassigned as they are optional.
Below is the list of some of most commonly used Services and their associated roles.
|Hive||Hive Metastore server, hiveserver2, gateway|
|Impala||Impala daemon, Statestore, Catalog server|
|HBase||Master, Regionserver, Thrift server|
|Spark||History server, gateway|
|YARN||Nodemanager, Jobhistory server, gateway|
|Kafka||Kafka Broker, Kafka MirrorMaker, gateway|