Apache Solr requires Java 1.6 or more to run, so it is important to make sure you have the correct version of Java by calling java –version, as shown in the following screenshot:

Once you have the correct Java version, you need a servlet container such as Tomcat, Jetty, Resin, Glassfish, or Weblogic installed on your machine. If you intend to use a jetty-based demo server, then you would not require a container.

The Apache Solr distribution comes as a single zipped folder. You can download the stable installer from http://lucene.apache.org/solr/ or from its nightly builds running on the same site. To run Solr in Windows, download the zip file from the Apache mirror site for Linux, UNIX, and other such flavors; you can download the .gzip/.tgz version. In Windows, you can simply unzip your file, and in UNIX, you can run the following command:

$ tar –xvzf solr-<major-minor version>.tgz

Another way is to build Apache Solr from a source. This will be required if you are going to modify or extend the Apache Solr source for your own handler, plugin, and others. You need Java SE 7 JDK (which stands for Java Development Kit) or JRE (which stands for Java Runtime Environment), Apache Ant distribution (1.8.2 or more), and Apache Ivy (2.2.0+). You can compile the source by simply navigating to the Solr folder and running ant from there.

When you unzip Solr, it extracts the following folders:

Now, declare $JAVA_HOME to point to your JDK/JRE. You will find the jetty server in the solr<version>/example folder. Once you unzip solr-<major-minor version>.tgz, all you need to do is go to solr<version>/example and run the following command:

$ $JAVA_HOME/bin/java –jar start.jar

$ bin/slor start

The default jetty instance will run on port 8983, and you can access the Solr instance by visiting the following URL: http://localhost:8983/Solr/browse. It shows a default search screen as shown in the following screenshot:

If your system default is Locale, or character set is non-English (that is, en/en-US), for the sake of safety you can override your system defaults for Solr by passing –Duser.language=en –Duser.country=US in your jetty to ensure smooth running of Solr.

It is relatively easy to set up Apache Solr on any J2EE container. It requires deployment of the Apache Solr application war file using the standard J2EE application deployment of any container. Another additional step that the Apache Solr application needs is the location of the Apache Solr home folder. This can either be set through Java options by setting the following environment variables or updating the container start up script:

$ export JAVA_OPTS="$JAVA_OPTS -Dsolr.solr.home=/opt/solr/example"

Alternatively, you can configure JNDI lookup for the java:comp/env/solr/home resource by pointing it to the Solr home folder. In Tomcat, this can be done by creating a context XML file with a chosen name (context.xml) in $CATALINA_HOME/conf/Catalina/localhost/context.xml, and adding the following entries:

<?xml version="1.0" encoding="utf-8"?>
<Context docBase="<solr-home>/example/solr/solr.war" debug="0" crossContext="true">
  <Environment name="solr/home" type="java.lang.String" value="<solr-home>/example/solr" override="true"/>
</Context>

Once you are done with the installation of Apache Solr, you can simply run examples by going to the examples/exampledocs folder and running:

java -jar post.jar solr.xml monitor.xml

post.jar is a utility provided by Solr to upload the data to Apache Solr for indexing. When it is run, the post.jar file simply uploads all the files that are passed as a parameter to Apache Solr for indexing, and Solr indexes these files and stores them in its repository. Now, try accessing your instance by typing http://localhost:8983/solr/browse; you should find a sample search interface with some information in it, as shown in the following screenshot:

In this section, we will try and understand the common problems faced while running Solr instances: