Setting up LLAP

Using Ambari, you can set up basic, low-latency analytical processing (LLAP) by accepting the default llap queue, changing some YARN queue properties, and adding a HiveServer property to hive-site.xml.

You have installed Ambari 2.7.x or later.
You added and started YARN, Tez, and dependencies that Ambari prompts you to add.
You added, started, and can run conventional queries from the Hive service.
If enabled, you disabled maintenance mode for the Hive service and target host for HiveServer Interactive (HSI); otherwise, enabling LLAP fails to install HSI. Alternatively, you need to install HiveServer Interactive on the Ambari server as follows:
```
curl -u admin:<password> -H "X-Requested-By:ambari" -i -X POST http://host:8080/api/v1/clusters/<cluster_name>/hosts/<host_name>/host_components/HIVE_SERVER_INTERACTIVE
```

The Interactive Query control displays a range of values for default Maximum Total Concurrent Queries based on the number of nodes that you select for LLAP processing and the number of CPUs in the Hive LLAP cluster. The Ambari wizard typically calculates appropriate values for LLAP properties in Interactive Query, so you can usually accept the defaults.

When you enable Interactive Query, the Run as end user and Hive user security settings have no effect. These controls affect batch-processing mode.