The riak_search OTP application provides Riak with the capability to act as a
text search engine similar to Apache’s Lucene. Previously Riak Search was a
release in it’s own right. Since then Basho has decided it would be easier for
our users if Search was simply a set of functionality that can be enabled via a
config option. For that reason, if you want to use Search you’ll have to build
a Riak release and enable it.