After initial installation, you can use the Add a Service wizard to add and configure new service instances. For example, you may want to add a service such as Oozie that you did not select in the wizard during the initial installation.
If you have installed a CDH4 cluster, you can use Add a Service to add the YARN service to enable MapReduce version 2 (MRv2). By default, the initial installation configures and enables only the original MapReduce service (though you can use the Custom option in the wizard to include it). If you add both versions of MapReduce, the original MapReduce service will be given a higher alternatives priority by default, so that the MRv1 configuration will take priority. (You can change this by changing the values of the Alternatives Priority in the MapReduce or YARN configuration settings.)
You can also use Add a Service to install Flume NG. Because Flume requires the addition of a configuration file to specify the agent configuration, it must be added separately after the wizard has finished.
Cloudera Impala can be added using the initial installation wizard, and does not need to be added separately.
The current upstream MRv2 release is not considered stable at this time. Therefore, it is not recommended for use in production at this time.
Adding a Service
- Click the Services tab, then choose All Services.
- From the Actions menu, select Add a Service. A list of possible services are displayed. You can add one type of service at a time.
- Follow the instructions in the Add Service wizard to add the service. As you go through the wizard pages, Cloudera Manager will recommend assignments of service roles to hosts based on the host properties and existing roles on the host; you can modify these assignments if necessary. Cloudera Manager will also recommend configuration settings, such as data directory paths and heap sizes. You can modify the settings as indicated before continuing.
- If you accept the configuration settings by clicking Continue in the wizard's configuration settings page, Cloudera Manager will create the service and its roles and with your specified configuration settings.
- If you click Skip in the wizard's configuration settings page, Cloudera Manager will create the service and its roles without the configuration settings, and you will need to configure the settings later in the Service > Configuration tab for the new service.
- When the wizard is finished:
- If the new service is not dependent on another service — for example, ZooKeeper — and if you continued with the recommended configurations, the service is configured and started automatically. If you skipped the configuration settings page, the new service will not be configured or started automatically. You must configure the settings for the new service in the Service > Configuration pages and then start it.
- If you added a service that is dependent on another service — for example, HBase is dependent on HDFS and ZooKeeper — the new service is not started automatically if the dependent service has an outdated configuration.
- If you added a service that is dependent on another service that was stopped at the time you used the Add Service wizard, the wizard will start the dependent service for you and perform any other steps required to prepare the cluster for the new service. When you are ready, start the new service.
- If you added a service that is dependent on another service that was already started at the time you used the Add Service wizard, its configurations might be out of date if you continued with the recommended configurations. Or, you may need to update its configurations so that the new service works correctly. Restart the dependent service before you start the new service.
For information about the order in which to start services, see Starting, Stopping, and Restarting Services.
You can verify the new service is started properly by navigating to Services > Status and checking the health status for the new service. If the Health Status is Good, then the service is started properly.
The current upstream MRv2 release is not yet stable, and should not be considered production-ready at this time. It is given by default a lower alternatives priority than MRv1.
Initializing the ZooKeeper Service
When adding the ZooKeeper service, the Add Service wizard automatically initializes the data directories. If you quit the Add Service wizard or it does not finish successfully, you can initialize the directories outside the wizard by doing these steps:
- Choose Initialize from the Actions menu in the ZooKeeper > Status tab.
- Click Initialize again to confirm.
If the data directories are not initialized, the ZooKeeper nodes cannot be started. If you add additional ZooKeeper roles after the initial installation, you must initialize their data directories before you start those roles.
Creating Beeswax's Hive Warehouse Directory
When adding the Hue service, the Add Service wizard automatically creates a Hive warehouse directory for Beeswax. If you quit the Add Service wizard or it does not finish, you can create the Hive warehouse directory outside the wizard by doing these steps:
- In the Hue > Status tab, choose Create Beeswax's Hive Warehouse Directory from the Actions menu.
- Click Create Beeswax's Hive Warehouse Directory again to confirm.