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The "SolrCloud" page has been changed by YonikSeeley. The comment on this change is: start simple replicated example. http://wiki.apache.org/solr/SolrCloud?action=diff&rev1=21&rev2=22 -------------------------------------------------- Solr embeds and uses Zookeeper as a repository for cluster configuration and coordination - think of it as a distributed filesystem. Since we'll need two solr servers for this example, simply make a copy of the example directory for the second server. + {{{ cp -r example example2 }}} - === Simple two shard cluster === + This example simply creates a cluster consisting of two solr servers representing two different shards of a collection. + + Since we'll need two solr servers for this example, simply make a copy of the example directory for the second server. + + {{{ + cp -r example example2 + }}} This command starts up a Solr server and bootstraps a new solr cluster. + {{{ cd example java -Dbootstrap_confname=myconf -Dbootstrap_confdir=./solr/conf -DzkRun -jar start.jar }}} - * {{{-DzkRun}}} tells solr to run a single standalone zookeeper server as part of this Solr server. * {{{-Dbootstrap_confname=myconf}}} tells this solr node to use the "myconf" configuration stored within zookeeper. * {{{-Dbootstrap_confdir=./solr/conf}}} since "myconf" does not actually exist yet, this parameter causes the local configuration directory {{{./solr/conf}}} to be uploaded to zookeeper as the "myconf" config. @@ -37, +44 @@ You can see from the zookeeper browser that the Solr configuration files were uploaded under "myconf", and that a new document collection called "collection1" was created. Under collection1 is a list of shards, the pieces that make up the complete collection. - Now we want to start up our second server, assigning it a different shard, or piece of the collection. - Simply change the shardId parameter for the appropriate solr core in solr.xml: + Now we want to start up our second server, assigning it a different shard, or piece of the collection. Simply change the shardId parameter for the appropriate solr core in solr.xml: + {{{ cd example2 perl -pi -e 's/shard1/shard2/g' solr/solr.xml #note: if you don't have perl installed, you can simply hand edit solr.xml, changing shard1 to shard2 }}} - Then start the second server, pointing it at the cluster: + {{{ java -Djetty.port=7574 -DhostPort=7574 -DzkHost=localhost:9983 -jar start.jar }}} - * {{{-Djetty.port=7574}}} is just one way to tell the Jetty servlet container to use a different port. * {{{-DhostPort=7574}}} tells Solr what port the servlet container is running on. * {{{-DzkHost=localhost:9983}}} points to the Zookeeper ensemble containing the cluster state. In this example we're running a single Zookeeper server embedded in the first Solr server. By default, an embedded Zookeeper server runs at the Solr port plus 1000, so 9983. @@ -57, +63 @@ If you refresh the zookeeper browser, you should now see both shard1 and shard2 in collection1. Next, index some documents to each server: + {{{ cd exampledocs java -Durl=http://localhost:8983/solr/collection1/update -jar post.jar ipod_video.xml java -Durl=http://localhost:7574/solr/collection1/update -jar post.jar monitor.xml }}} - And now, a request to either server with "distrib=true" results in a distributed search that covers the entire collection: http://localhost:8983/solr/collection1/select?distrib=true&q=*:* If at any point you wish to start over fresh or experiment with different configurations, you can delete all of the cloud state contained within zookeeper by simply deleting the solr/zoo_data directory after shutting down the servers. + + === Simple two shard cluster with shard replicas === + This example will simply build off of the previous example by creating another copy of shard1 and shard2. Extra shard copies can be used for high availability and fault tolerance, or simply for increasing the query capacity of the cluster. + + First, run through the previous example so we already have two shards and some documents indexed into each. Then simply make a copy of those two servers: + + {{{ + cp -r example exampleB + cp -r example2 example2B + }}} + Then start the two new servers on different ports, each in its own window: + + {{{ + cd exampleB + java -Djetty.port=8900 -DhostPort=8900 -DzkHost=localhost:9983 -jar start.jar + }}} + {{{ + cd example2B + java -Djetty.port=7500 -DhostPort=7500 -DzkHost=localhost:9983 -jar start.jar + }}} + Refresh the zookeeper browser page http://localhost:8983/solr/admin/zookeeper.jsp and verify that 4 solr nodes are up, and that each shard is present at 2 nodes. + + Now send a query to any of the servers to query the cluster: + + http://localhost:7500/solr/collection1/select?distrib=true&q=*:* + + Send this query multiple times and observe the logs from the solr servers. From your web browser, you may need to hold down CTRL while clicking on the browser refresh button to bypass the HTTP caching in your browser. You should be able to observe Solr load balancing the requests across shard replicas, using different servers to satisfy each request. There will be a log statement for the top-level request in the server the browser sends the request to, and then a log statement for each sub-request that are merged to produce the complete response. + == ZooKeeper == Multiple Zookeeper servers running together for fault tolerance and high availability is called an ensemble. For production, it's recommended that you run an external zookeeper ensemble rather than having Solr run embedded servers.
