Elasticsearch is a real time search engine where a change to an index will be propegated to the whole cluster within a second.
An elasticsearch cluster indicated as one or more nodes, collection of nodes containing all the data, default cluster name is elasticserach.
A node
is a single server
and part of a cluster, node participate in searching and indexing.
Index
is collection of documents equavalent to a database
within a relational system, index name must be lowercase
Type is represetn a class = table