Apache Solr is a subproject of Apache Lucene, which is the indexing technology behind most recently created search and index technology. Solr is a search engine at heart, but it is much more than that. It is a NoSQL database with transactional support. It is a document database that offers SQL support and executes it in a distributed manner.
Sound interesting? Join me for a closer look. (Full disclosure: I work for Lucidworks, which employs many of the key contributors to the Solr project.)
You need a decent machine (or just use an AWS instance) with ideally 8GB or more RAM. You can find Solr at http://lucene.apache.org/solr. You also need the Java Virtual Machine version 8. Unzip/untar Solr into a directory, make sure JAVA_HOME is set, and that the java binary is in your path. Change to the directory Solr is in and type
bin/solr start -e cloud -noprompt. This starts a two node cluster on your laptop with a sample collection called gettingstarted already loaded.