Elasticsearch Nodes

Elasticsearch nodes are individual instances of Elasticsearch servers that are part of a cluster. Each node stores data and participates in the cluster’s indexing and search capabilities, playing a critical role in the distributed architecture of Elasticsearch.​

Key Points about Elasticsearch Nodes:

A node is a single server or instance running Elasticsearch, identified by a unique name.

Nodes collectively form a cluster, which is a group of Elasticsearch nodes working together.

Nodes can have different roles:

• Master Node: Manages the cluster state and handles cluster-wide actions like adding/removing nodes and creating/deleting indices.
• Data Node: Stores data and executes data-related operations such as searches and aggregations.
• Client (Coordinating) Node: Routes requests to the appropriate nodes but does not hold data.
• Other special roles include ingestion and machine learning nodes.

Nodes communicate through TCP ports (commonly 9200 for REST API and 9300 for node-to-node communication).

Elasticsearch distributes data across nodes using shards, enabling horizontal scalability, fault tolerance, and high availability.​

In essence, nodes are the building blocks of an Elasticsearch cluster, with each node running on a server (physical or virtual) and working in coordination to provide fast search and analytics on distributed data.

To list all nodes with their attributes we can run this command in Kibana DevTools:

GET /_cat/nodes?v

Output example:

ip            heap.percent ram.percent cpu load_1m load_5m load_15m    node.role       master name

10.199.43.136           44          61   5    1.69    1.71     1.51 cdfhilmrstw -      default-2

10.199.6.164            38          55   4    0.96    1.40     1.33 cdfhilmrstw -      default-1

10.199.30.70            25          51   9    1.61    1.57     1.06 cdfhilmrstw -      data-0

10.199.38.215           46         100  13    1.69    1.71     1.51 cdfhilmrstw -      data-1

10.199.1.249            81          76  30    0.96    1.40     1.33 cdfhilmrstw *      monitoring-1

10.199.32.134           75         100  27    1.69    1.71     1.51 cdfhilmrstw -      monitoring-0

10.199.23.94            77         100  26    1.61    1.57     1.06 cdfhilmrstw -      monitoring-2

10.199.18.75            23          91  19    1.61    1.57     1.06 cdfhilmrstw -      default-0

10.199.15.193           59          56   5    0.96    1.40     1.33 cdfhilmrstw -      data-2

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