blob: 6a737f887f603fd24b9da4e6ee395d9d9782547f [file] [log] [blame]
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="impala_ha">
<title>Configuring Impala for High Availability</title>
<prolog>
<metadata>
<data name="Category" value="Impala"/>
<data name="Category" value="Administrators"/>
<data name="Category" value="High Availability"/>
<data name="Category" value="Configuring"/>
<data name="Category" value="Data Analysts"/>
</metadata>
</prolog>
<conbody>
<p>The Impala StateStore checks on the health of all Impala daemons in a cluster, and
continuously relays its findings to each of the daemons. The Catalog stores metadata of
databases, tables, partitions, resource usage information, configuration settings, and other
objects managed by Impala. If StateStore and Catalog daemons are single instances in an Impala
cluster, it will create a single point of failure. Although Impala coordinators/executors
continue to execute queries if the StateStore node is down, coordinators/executors will not
get state updates. This causes degradation of admission control &amp; cluster membership
updates. To mitigate this, a pair of StateStore and Catalog instances can be deployed in an
Impala cluster so that Impala cluster could survive failures of StateStore or Catalog.</p>
<p><b>Prerequisite:</b></p>
<p>To enable High Availability for Impala CatalogD and StateStore, you must configure at least
two Impala CatalogD, two StateStore instances on two different nodes.<note
id="note_dg1_qhh_fcc" type="note">CatalogD HA and Statestore HA are independent features.
Users can enable CatalogD HA, Statestore HA, or both CatalogD HA and Statestore
HA.</note></p>
<p outputclass="toc"/>
</conbody>
</concept>