Configure other LLAP properties

Configuring LLAP involves setting properties in YARN and Hive. After you configure the llap queue, you need to go back to the Hive configuration to continue setting up low-latency analytical processing (LLAP).

In this task, you accept the Ambari configuration of a number of properties or reconfigure the properties. Ambari generally configures the number of nodes that run an LLAP daemon and total concurrent queries depending on the size of the llap queue. Ambari also attempts to correctly configure the following properties for your particular cluster:

Memory per Daemon

YARN container size for each daemon (MB)

In-Memory Cache per Daemon

Size of the cache in each container (MB)

Number of executors per LLAP Daemon

The number of fragments that can execute in parallel on a daemon

Use the slider controls to change or restore settings:

To set the value outside the slider range, you move your pointer over the field to enable the hover actions, and select Override.

1. Accept or change the Number of Nodes Used By Hive LLAP (num_llap_nodes property). For example, accept using 2 nodes for LLAP.

   

2. Accept the Maximum Total Concurrent Queries (hive.server2.tez.sessions.per.default.queue property), or make changes.
3. Check Memory per Daemon (hive.llap.daemon.yarn.container.mb property) and In-Memory Cache per Daemon (hive.llap.io.memory.size property).

   

   This memory (hive.llap.daemon.yarn.container.mb) plus the cache (hive.llap.io.memory.size) must fit within the container size specified for the YARN container. The YARN container configuration setting appears in Services > YARN > Configs > Settings.
4. Accept the Number of Executors per LLAP Daemon (hive.llap.daemon.num.executors), or change this setting if you know what you are doing, and check that the hive.llap.io.threadpool.size is the same value.
5. Save any Hive configuration changes, and in Services > YARN > Settings > Memory - Node, check that the Minimum Container Size (Memory) for YARN is low.
   The value should rarely exceed 1024 MB.
6. Set the Maximum Container Size (Memory) to the same value as the Memory Allocated for All YARN Containers on a Node.

   

7. In Ambari, select Services > YARN > Configs > Advanced.
8. In Custom yarn-site, add the following properties unless, upon attempting to add these properties, Ambari indicates the properties are already added:yarn.resourcemanager.monitor.capacity.preemption.natural_termination_factor (value = 1) and yarn.resourcemanager.monitor.capacity.preemption.total_preemption_per_round (as described below).
   Calculate the value of the total preemption per round by dividing 1 by the number of cluster nodes. Enter the value as a decimal.
   For example, if your cluster has 20 nodes, then divide 1 by 20 and enter 0.05 as the value of this property setting.
9. Save YARN changes, and go back to the Hive configuration.