Book Image

Apache Solr Enterprise Search Server - Third Edition

By : David Smiley, Eric Pugh, Kranti Parisa, Matt Mitchell
Book Image

Apache Solr Enterprise Search Server - Third Edition

By: David Smiley, Eric Pugh, Kranti Parisa, Matt Mitchell

Overview of this book

<p>Solr Apache is a widely popular open source enterprise search server that delivers powerful search and faceted navigation features—features that are elusive with databases. Solr supports complex search criteria, faceting, result highlighting, query-completion, query spell-checking, relevancy tuning, geospatial searches, and much more.</p> <p>This book is a comprehensive resource for just about everything Solr has to offer, and it will take you from first exposure to development and deployment in no time. Even if you wish to use Solr 5, you should find the information to be just as applicable due to Solr's high regard for backward compatibility. The book includes some useful information specific to Solr 5.</p>
Table of Contents (19 chapters)
Apache Solr Enterprise Search Server Third Edition
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Setting up ZooKeeper for SolrCloud


ZooKeeper is the technology that keeps all the nodes in SolrCloud in sync, and in Chapter 10, Scaling Solr , we discussed how to leverage it. However, for convenience, we told Solr to run the ZooKeeper service internally (embedded, in-process) by passing the zkRun parameter to Solr on startup. While you could do that in production, you usually shouldn't because then you tie your ZooKeeper service to your Solr nodes. So imagine the scenario where you want to stop and restart Solr? Running embedded ZooKeeper means that you also take down one of your ZooKeeper nodes when you stop a Solr node. ZooKeeper has the concept of a quorum of servers that all host the exact same configuration file, and to have a valid quorum, at least half of the ZooKeeper processes must be functioning. If you have three Solr nodes running embedded ZooKeeper, and you restart two of the Solr nodes, you no longer have a quorum of 2 out of 3 servers, a situation called split brain...