When learning Elasticsearch, it’s important to start with a good foundational understanding of key concepts and terms.  In this post we define and explain important Elasticsearch concepts.

Elasticsearch Terms and Definitions

Elasticsearch Node.  An Elasticsearch node is a single Elasticsearch process, and the minimum number of nodes for a highly available Elasticsearch cluster is three. Continue reading about Elasticsearch Nodes.

Elasticsearch Cluster.  An Elasticsearch cluster is one or more Elasticsearch nodes with the same cluster identification.  Continue reading about Elasticsearch Clusters.

Elasticsearch Index.  An Elasticsearch index is a collection of documents in Elasticsearch.  Each index is split into shards. Continue reading about Elasticsearch Indexing.

Elasticsearch Shard.  Elasticsearch shards enable parallelization of data processing across both a single and multiple Elasticsearch nodes. By default, Elasticsearch automatically manages shard allocation within the node(s). Continue reading about Elasticsearch Shards.

Elasticsearch Replica.  Elasticsearch replicas serve as a backup for shards and also aid in search performance by providing additional capacity.   Elasticsearch automatically creates five primary shards and one replica for every index. Continue reading about Elasticsearch Replicas.

Elasticsearch Port.  The default Elasticsearch port is 9200/tcp.  The Elasticsearch port can be modified in the configuration file, elasticsearch.yml.

Elasticsearch Query.  Elasticsearch queries are sub-divided into two categories:  leaf queries and compound queries.  Elasticsearch leaf queries search for specific values within a field or field(s).  Elasticsearch compound queries combine multiple queries together.  Continue reading about how to Query Elasticsearch with Boolean Queries.

Elasticsearch Pagination.  Elasticsearch pagination is the setting to return a maximum number of results.  This number changes frequently.  Elasticsearch pagination can be changed by adding a size parameter to the search request.

Elasticsearch as a Service.  Elasticsearch as a Service provides 24/7 monitoring, support, and maintenance to maximize performance and uptime.  Elasticsearch as a Service is typically provided by a team of engineers who have extensive experience with Elasticsearch management. Continue reading about Elasticsearch as a Service.

Managed Elasticsearch.  Managed Elasticsearch is used interchangeably with Elasticsearch as a Service.  Managed Elasticsearch provides 24/7 monitoring, support, and maintenance to maximize performance and uptime.  Managed Elasticsearch is typically provided by a team of engineers who have extensive experience with Elasticsearch management. Continue reading about Managed Elasticsearch.

Hosted Elasticsearch.  Hosted Elasticsearch is a type of managed Elasticsearch where the service provider hosts their clients’ clusters on the service provider’s own environment.  Hosted Elasticsearch tends to increase latency and cost more than when Elasticsearch is run in a client’s own environment.  Continue reading about Hosted Elasticsearch.