Installing Solr

Introduction

Solr is a java webapp used by CKAN as a backend for dataset indexing. Solr shall be installed in a tomcat instance on its own, in order to decouple it from other installed webapps (i.e. GeoNetwork, Tolomeo).

It is expected that the base system has already been properly installed and configured as described in Tomcat Installation.

In such document there are information about how to install some required base components, such as the JDK and Apache Tomcat.

Installing Solr

We’re going to install Solr Catalina base in /var/lib/tomcat/solr; we’ll put its configuration files in /etc/solr.

Install

Download solr (it’s a 127MB .tgz file) and untar it:

cd /root/download
wget http://archive.apache.org/dist/lucene/solr/4.5.0/solr-4.5.0.tgz
tar xzvf  solr-4.5.0.tgz

Make sure you already:

• created the tomcat user (Create tomcat user)
• installed tomcat (Install Tomcat files)
• created the base catalina template (Create base template)

Create catalina base directory for solr:

cp -a /var/lib/tomcat/base/  /var/lib/tomcat/solr

Copy .war file

cp -av /root/download/solr-4.5.0/dist/solr-4.5.0.war /var/lib/tomcat/solr/webapps/solr.war

Copy configuration files

mkdir -p /etc/solr/ckan
cp -r /root/download/solr-4.5.0/example/solr/collection1/conf /etc/solr/ckan

Create file /etc/solr/solr.xml

<solr persistent="true" sharedLib="lib">
   <cores adminPath="/admin/cores" defaultCoreName="ckan">
      <core name ="ckan-schema-2.0" instanceDir="ckan">
         <!-- <property name="dataDir" value="/var/lib/solr/data/ckan" /> -->
      </core>
   </cores>
</solr>

Copy libs

mkdir -p /opt/solr/libs
cp solr-4.5.0/dist/*.jar                        /opt/solr/libs
cp solr-4.5.0/contrib/analysis-extras/lib/*     /opt/solr/libs
cp solr-4.5.0/contrib/clustering/lib/*          /opt/solr/libs
cp solr-4.5.0/contrib/dataimporthandler/lib/*   /opt/solr/libs
cp solr-4.5.0/contrib/extraction/lib/*          /opt/solr/libs
cp solr-4.5.0/contrib/langid/lib/*              /opt/solr/libs
cp solr-4.5.0/contrib/uima/lib/*                /opt/solr/libs
cp solr-4.5.0/contrib/velocity/lib/*            /opt/solr/libs

Backup solr config files

cp /etc/solr/ckan/conf/solrconfig.xml /etc/solr/ckan/conf/solrconfig.xml.orig

Edit config file, commenting out all the <lib dir= ..... entries, and add:

<lib dir="/opt/solr/libs/" regex=".*\.jar" />

Create data dir:

mkdir /var/lib/tomcat/solr/data

Edit file /var/lib/tomcat/solr/bin/setenv.sh. We’ll set here some system vars used by tomcat, by the JVM, and by the webapp itself

export CATALINA_BASE=/var/lib/tomcat/solr
export CATALINA_HOME=/opt/tomcat/
#export CATALINA_PID=$CATALINA_BASE/work/pidfile.pid

export JAVA_OPTS="$JAVA_OPTS -Xms512m -Xmx800m -XX:MaxPermSize=256m"

export JAVA_OPTS="$JAVA_OPTS -Dsolr.solr.home=/etc/solr/"
export JAVA_OPTS="$JAVA_OPTS -Dsolr.data.dir=$CATALINA_BASE/data"

Make setenv.sh executable:

chmod +x /var/lib/tomcat/solr/bin/setenv.sh

Edit server.xml

Solr is an ancillary application, so we may want to keep the default 8080 port for the main application, such as GeoNetwork. We will change the tomcat ports in file /var/lib/tomcat/solr/conf/server.xml in this way:

• 8004 for commands to catalina instance
• 8081 for the HTTP connection

We won’t need the AJP connection, since Solr will be not exposed to the internet via apache httpd, so comment out the AJP connector.

See also Installed applications.

Webapp directory ownership

Set the ownership of the solr/ related directories to user tomcat

chown tomcat: -R /var/lib/tomcat/solr
chown tomcat: -R /etc/solr/

In order to make solr work with CKAN, a schema needs to be set. It will be set in a following section, so we do not want to start solr right away.

Starting and stopping Solr

Autostart

The standard Systemd way for setting Solr as an autostarting service is:

systemctl enable tomcat@solr

Commands

Once Solr has been installed, you can start it with:

systemctl start  tomcat@solr

These are the commands for starting, stopping and querying Solr:

• systemctl start  tomcat@solr
• systemctl stop   tomcat@solr
• systemctl status tomcat@solr