docs/topics/impala_install.xml

<?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="install">

  <title><ph audience="standalone">Installing Impala</ph><ph audience="integrated">Impala Installation</ph></title>
  <prolog>
    <metadata>
      <data name="Category" value="Impala"/>
      <data name="Category" value="Installing"/>
      <data name="Category" value="Administrators"/>
    </metadata>
  </prolog>

  <conbody>

    <p>
      <indexterm audience="hidden">installation</indexterm>
      <indexterm audience="hidden">pseudo-distributed cluster</indexterm>
      <indexterm audience="hidden">cluster</indexterm>
      <indexterm audience="hidden">DataNodes</indexterm>
      <indexterm audience="hidden">NameNode</indexterm>
      <indexterm audience="hidden">impalad</indexterm>
      <indexterm audience="hidden">impala-shell</indexterm>
      <indexterm audience="hidden">statestored</indexterm>
      Impala is an open-source analytic database for Apache Hadoop
      that returns rapid responses to queries.
    </p>

    <p>
      Follow these steps to set up Impala on a cluster by building from source:
    </p>

<!-- Steps adapted from http://impala.apache.org/downloads.html -->

    <ul>
      <li>
        <p>
          Download the latest release. See
          <xref href="http://impala.apache.org/downloads.html" scope="external" format="html">the Impala downloads page</xref>
          for the link to the latest release.
        </p>
      </li>
      <li>
        <p>
          Check the <filepath>README.md</filepath> file for a pointer
          to the build instructions.
        </p>
      </li>
      <li>
        <p>
          Please check the MD5 and SHA1 and GPG signature, the latter by using the code signing keys of the release managers.
        </p>
      </li>
      <li>
        <p>
          Developers interested in working on Impala can clone the Impala source repository:
<codeblock>
git clone https://gitbox.apache.org/repos/asf/impala.git
</codeblock>
        </p>
      </li>
    </ul>

  </conbody>

  <concept id="install_details">

    <title>What is Included in an Impala Installation</title>

    <conbody>

      <p>
        Impala is made up of a set of components that can be installed on multiple nodes throughout your cluster.
        The key installation step for performance is to install the <cmdname>impalad</cmdname> daemon (which does
        most of the query processing work) on <i>all</i> DataNodes in the cluster.
      </p>

      <p>
        Impala primarily consists of these executables, which should be available after you build from source:
      </p>

      <ul>
        <li>
          <p>
            <cmdname>impalad</cmdname> - The Impala daemon. Plans and executes queries against HDFS, HBase, <ph rev="2.2.0">and Amazon S3 data</ph>.
            <xref href="impala_processes.xml#processes">Run one impalad process</xref> on each node in the cluster
            that has a DataNode.
          </p>
        </li>

        <li>
          <p>
            <cmdname>statestored</cmdname> - Name service that tracks location and status of all
            <codeph>impalad</codeph> instances in the cluster. <xref href="impala_processes.xml#processes">Run one
            instance of this daemon</xref> on a node in your cluster. Most production deployments run this daemon
            on the namenode.
          </p>
        </li>

        <li rev="1.2">
          <p>
            <cmdname>catalogd</cmdname> - Metadata coordination service that broadcasts changes from Impala DDL and
            DML statements to all affected Impala nodes, so that new tables, newly loaded data, and so on are
            immediately visible to queries submitted through any Impala node.
<!-- Consider removing this when 1.2 gets far in the past. -->
            (Prior to Impala 1.2, you had to run the <codeph>REFRESH</codeph> or <codeph>INVALIDATE
            METADATA</codeph> statement on each node to synchronize changed metadata. Now those statements are only
            required if you perform the DDL or DML through an external mechanism such as Hive <ph rev="2.2.0">or by uploading
            data to the Amazon S3 filesystem</ph>.)
            <xref href="impala_processes.xml#processes">Run one instance of this daemon</xref> on a node in your cluster,
            preferably on the same host as the <codeph>statestored</codeph> daemon.
          </p>
        </li>

        <li>
          <p>
            <cmdname>impala-shell</cmdname> - <xref href="impala_impala_shell.xml#impala_shell">Command-line
            interface</xref> for issuing queries to the Impala daemon. You install this on one or more hosts
            anywhere on your network, not necessarily DataNodes or even within the same cluster as Impala. It can
            connect remotely to any instance of the Impala daemon.
          </p>
        </li>
      </ul>

      <p>
        Before starting working with Impala, ensure that you have all necessary prerequisites. See
        <xref href="impala_prereqs.xml#prereqs"/> for details.
      </p>
    </conbody>
  </concept>

</concept>