74 lines
2.4 KiB
Markdown
74 lines
2.4 KiB
Markdown
---
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layout: default
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title: Nodes APIs
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---
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# Nodes API
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The nodes API makes it possible to retrieve information about individual nodes within your cluster.
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## Node filters
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Use the `<node-filters>` parameter to filter the target set of nodes in the API response.
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Parameter | Type | Description
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:--- |:-------| :---
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`<node-filters>` | String | A comma-separated list of resolution mechanisms that OpenSearch uses to identify cluster nodes.
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Node filters support several node resolution mechanisms:
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- Predefined constants: `_local`, `_cluster_manager`, or `_all`.
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- An exact match for `nodeID`
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- A simple case-sensitive wildcard pattern matching for `node-name`, `host-name`, or `host-IP-address`.
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- Node roles where the `<bool>` value is set either to `true` or `false`:
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- `cluster_manager:<bool>` refers to all cluster manager-eligible nodes.
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- `data:<bool>` refers to all data nodes.
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- `ingest:<bool>` refers to all ingest nodes.
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- `voting_only:<bool>` refers to all voting-only nodes.
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- `ml:<bool>` refers to all machine learning (ML) nodes.
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- `coordinating_only:<bool>` refers to all coordinating-only nodes.
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- A simple case-sensitive wildcard pattern matching for node attributes: `<node attribute*>:<attribute value*>`. The wildcard matching pattern can be used in both the key and value at the same time.
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Resolution mechanisms are applied sequentially in the order specified by the client. Each mechanism specification can either add or remove nodes.
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To get statistics from the elected cluster manager node only, use the following query :
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```json
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GET /_nodes/_cluster_manager/stats
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```
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To get statistics from nodes that are data-only nodes, use the following query:
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```json
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GET /_nodes/data:true/stats
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```
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### Order of resolution mechanisms
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The order of resolution mechanisms is applied sequentially, and each can add or remove nodes. The following examples yield different results.
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To get statistics from all the nodes except the cluster manager node, use the following query:
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```json
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GET /_nodes/_all,cluster_manager:false/stats
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```
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However, if you switch the resolution mechanisms, the result will include all the cluster nodes, including the cluster manager node:
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```json
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GET /_nodes/cluster_manager:false,_all/stats
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``` |