Cloud Search

Elasticsearch is an open source, distributed, restful search engine based on lucene. Designed for cloud computing, can achieve real-time search, stable, reliable, fast, easy to install and use. Supports the use of json through http for data indexing.
Elasticsearch is distributed. There is no need for other components, distribution is real-time, is called "push replication."
Elasticsearch fully supports apache lucene's near-real-time search.
Processing multi-tenant (multitenancy) does not require special configuration, while solr requires more advanced settings.
Elasticsearch adopts the concept of gateway, which makes the backup easier.

Each node forms a peer-to-peer network structure, and some nodes will automatically assign other nodes to work on their behalf when some nodes fail.
CloudSearch supports faceted searching, free text searching, text processing, Boolean expressions, customized relevance ranking, field-based sorting, and other advanced functions
Elasticsearch is document-oriented (documentoriented), which means it can store the entire object or document (document). However, it not only stores, but also indexes the contents of each (index) document so that it can be searched. In elasticsearch, you can index, search, sort, filter documents (rather than rows of data). This way of understanding data is completely different, which is one of the reasons why elasticsearch can perform complex full-text searches.
Solr is a powerful solution for traditional search applications, but elasticsearch is more suitable for emerging real-time search applications.

ranked searching -- best results returned first
many powerful query types: phrase queries, wildcard queries, proximity queries, range queries and more
fielded searching (e.g. title, author, contents)
sorting by any field
multiple-index searching with merged results
allows simultaneous update and searching
flexible faceting, highlighting, joins and result grouping
fast, memory-efficient and typo-tolerant suggesters
pluggable ranking models, including the Vector Space Model and Okapi BM25
configurable storage engine (codecs)