Quick links
Overview
To put it simply, a node is a single server that is part of a cluster. Each node is assigned one or more roles, which describe the node’s responsibility and operations. Data nodes store the data, and participate in the cluster’s indexing and search capabilities, while cluster-managers nodes are responsible for managing the cluster’s activities and storing the cluster state, including the metadata.
While it is possible to run several node instances of OpenSearch on the same hardware, it’s considered a best practice to limit a server to a single running instance of OpenSearch.
Nodes connect to each other and form a cluster by using a discovery method.
Roles
Cluster-manager
Cluster-managers are in charge of cluster-wide settings and changes – deleting or creating indices and fields, adding or removing nodes and allocating shards to nodes. Each cluster has a single cluster-manager node that is elected from the cluster-manager eligible nodes using a distributed consensus algorithm and is reelected if the current cluster-manager node fails.
Coordinating node
Coordinating nodes are nodes that do not hold any configured role. They don’t hold data and are not part of the cluster-manager eligible group nor execute ingest pipelines. Coordinating nodes serve incoming search requests and act as the query coordinator running query and fetch phases, sending requests to every node that holds a shard being queried. The coordinating node also distributes bulk indexing operations and route queries to shards based on the node’s responsiveness.
How to reduce OpenSearch costs by optimizing your node roles
Watch the video below to learn how to save money on your deployment by optimizing your node roles.
