Apache Solr Reference Guide Covering Apache Solr 6.0

SolrCloud
Apache Solr includes the ability to set up a cluster of Solr servers that combines fault tolerance and high
availability. Called SolrCloud, these capabilities provide distributed indexing and search capabilities, supporting
the following features:
Central configuration for the entire cluster
Automatic load balancing and fail-over for queries
ZooKeeper integration for cluster coordination and configuration.
SolrCloud is flexible distributed search and indexing, without a master node to allocate nodes, shards and
replicas. Instead, Solr uses ZooKeeper to manage these locations, depending on configuration files and
schemas. Documents can be sent to any server and ZooKeeper will figure it out.
In this section, we'll cover everything you need to know about using Solr in SolrCloud mode. We've split up the
details into the following topics:
Getting Started with SolrCloud
How SolrCloud Works
Shards and Indexing Data in SolrCloud
Distributed Requests
Read and Write Side Fault Tolerance
SolrCloud Configuration and Parameters
Setting Up an External ZooKeeper Ensemble
Using ZooKeeper to Manage Configuration Files
ZooKeeper Access Control
Collections API
Parameter Reference
Command Line Utilities
SolrCloud with Legacy Configuration Files
ConfigSets API
Rule-based Replica Placement
Cross Data Center Replication (CDCR)
Getting Started with SolrCloud
SolrCloud is designed to provide a highly available, fault tolerant environment for distributing your indexed
content and query requests across multiple servers. It's a system in which data is organized into multiple pieces,
or shards, that can be hosted on multiple machines, with replicas providing redundancy for both scalability and
fault tolerance, and a ZooKeeper server that helps manage the overall structure so that both indexing and search
requests can be routed properly.
This section explains SolrCloud and its inner workings in detail, but before you dive in, it's best to have an idea of
what it is you're trying to accomplish. This page provides a simple tutorial to start Solr in SolrCloud mode, so you
can begin to get a sense for how shards interact with each other during indexing and when serving queries. To
that end, we'll use simple examples of configuring SolrCloud on a single machine, which is obviously not a real
production environment, which would include several servers or virtual machines. In a real production
environment, you'll also use the real machine names instead of "localhost" which we've used here.
In this section you will learn how to start a SolrCloud cluster using startup scripts and a specific configset.
This tutorial assumes that you're already familiar with the basics of using Solr. If you need a refresher,
please see the Getting Started section to get a grounding in Solr concepts. If you load documents as part
of that exercise, you should start over with a fresh Solr installation for these SolrCloud tutorials.
Apache Solr Reference Guide 6.0
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