• Started off as an scalable Lucene
• Horizontally scalable search engine
• Kibana is used as UI for elastic search because it doesn’t have its own UI like SOLR
• Logstash/Beats is used to feed data into elasticsearch.
• FileBeat can monitor log files, parse then and import them into ElasticSearch in real-time.
• Logstash also pushes data into Elasticsearch from many machines, not just log files.
• Default Port 9200
• There is no document types concept here.
• Index Lifecycle Management (ILM)

Logical Concepts/Terminologies

• Document - Documents are the things that you search for for example one product details can be considered one document.
• Indices - An index powers search into all documents within a collection of types. They contain inverted indices that let you search across everything within them at once.
• TF/IDF You know this already.
• Mapping - Mapping is a schema definition.

_Version

• Every document in ES has _version
• ES documents are immutable