[DOCS] Reword node roles docs (#69301)

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James Rodewig 2021-02-23 11:32:46 -05:00 committed by GitHub
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@ -46,9 +46,6 @@ means that filters such as `master:false` which remove nodes from the chosen
subset are only useful if they come after some other filters. When used on its
own, `master:false` selects no nodes.
NOTE: The `voting_only` role requires the {default-dist} of Elasticsearch and
is not supported in the {oss-dist}.
Here are some examples of the use of node filters with the
<<cluster-nodes-info,Nodes Info>> APIs.

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@ -17,8 +17,9 @@ requests to the appropriate node.
[[node-roles]]
==== Node roles
You can define the roles of a node by setting `node.roles`. If you don't
configure this setting, the node has the following roles by default:
You define a node's roles by setting `node.roles` in `elasticsearch.yml`. If you
set `node.roles`, the node is only assigned the roles you specify. If you don't
set `node.roles`, the node is assigned the following roles:
* `master`
* `data`
@ -32,7 +33,18 @@ configure this setting, the node has the following roles by default:
* `remote_cluster_client`
* `transform`
NOTE: If you set `node.roles`, the node is assigned only the roles you specify.
[IMPORTANT]
====
If you set `node.roles`, ensure you specify every node role your cluster needs.
Some {stack} features require specific node roles:
- {ccs-cap} and {ccr} require the `remote_cluster_client` role.
- {stack-monitor-app} and ingest pipelines require the `ingest` role.
- {fleet}, the {security-app}, and {transforms} require the `transform` role.
The `remote_cluster_client` role is also required to use {ccs} with these
features.
- {ml-cap} features, such as {anomaly-detect}, require the `ml` role.
====
As the cluster grows and in particular if you have large {ml} jobs or
{ctransforms}, consider separating dedicated master-eligible nodes from
@ -40,17 +52,17 @@ dedicated data nodes, {ml} nodes, and {transform} nodes.
<<master-node,Master-eligible node>>::
A node that has the `master` role (default), which makes it eligible to be
A node that has the `master` role, which makes it eligible to be
<<modules-discovery,elected as the _master_ node>>, which controls the cluster.
<<data-node,Data node>>::
A node that has the `data` role (default). Data nodes hold data and perform data
A node that has the `data` role. Data nodes hold data and perform data
related operations such as CRUD, search, and aggregations. A node with the `data` role can fill any of the specialised data node roles.
<<node-ingest-node,Ingest node>>::
A node that has the `ingest` role (default). Ingest nodes are able to apply an
A node that has the `ingest` role. Ingest nodes are able to apply an
<<pipeline,ingest pipeline>> to a document in order to transform and enrich the
document before indexing. With a heavy ingest load, it makes sense to use
dedicated ingest nodes and to not include the `ingest` role from nodes that have
@ -58,16 +70,15 @@ the `master` or `data` roles.
<<remote-node,Remote-eligible node>>::
A node that has the `remote_cluster_client` role (default), which makes it
eligible to act as a remote client. By default, any node in the cluster can act
as a cross-cluster client and connect to remote clusters.
A node that has the `remote_cluster_client` role, which makes it eligible to act
as a remote client.
<<ml-node,Machine learning node>>::
A node that has `xpack.ml.enabled` and the `ml` role, which is the default
behavior in the {es} {default-dist}. If you want to use {ml-features}, there
must be at least one {ml} node in your cluster. For more information about
{ml-features}, see {ml-docs}/index.html[Machine learning in the {stack}].
A node that has `xpack.ml.enabled` and the `ml` role. If you want to use
{ml-features}, there must be at least one {ml} node in your cluster. For more
information about {ml-features}, see {ml-docs}/index.html[Machine learning in
the {stack}].
<<transform-node,{transform-cap} node>>::
@ -161,10 +172,8 @@ node:
node.roles: [ data, master, voting_only ]
-------------------
IMPORTANT: The `voting_only` role requires the {default-dist} of {es} and is not
supported in the {oss-dist}. If you use the {oss-dist} and add the `voting_only`
role then the node will fail to start. Also note that only nodes with the
`master` role can be marked as having the `voting_only` role.
IMPORTANT: Only nodes with the `master` role can be marked as having the
`voting_only` role.
High availability (HA) clusters require at least three master-eligible nodes, at
least two of which are not voting-only nodes. Such a cluster will be able to
@ -181,7 +190,7 @@ Voting-only master-eligible nodes may also fill other roles in your cluster.
For instance, a node may be both a data node and a voting-only master-eligible
node. A _dedicated_ voting-only master-eligible nodes is a voting-only
master-eligible node that fills no other roles in the cluster. To create a
dedicated voting-only master-eligible node in the {default-dist}, set:
dedicated voting-only master-eligible node, set:
[source,yaml]
-------------------
@ -317,8 +326,8 @@ node.roles: [ ]
[[remote-node]]
==== Remote-eligible node
By default, any node in a cluster can act as a cross-cluster client and connect
to <<modules-remote-clusters,remote clusters>>. Once connected, you can search
A remote-eligible node acts as a cross-cluster client and connects to
<<modules-remote-clusters,remote clusters>>. Once connected, you can search
remote clusters using <<modules-cross-cluster-search,{ccs}>>. You can also sync
data between clusters using <<xpack-ccr,{ccr}>>.
@ -358,7 +367,7 @@ Otherwise, {ccs} fails when used in {ml} jobs or {dfeeds}. See <<remote-node>>.
{transform-cap} nodes run {transforms} and handle {transform} API requests. For
more information, see <<transform-settings>>.
To create a dedicated {transform} node in the {default-dist}, set:
To create a dedicated {transform} node, set:
[source,yaml]
----