Add search and warm node roles (#1006)

Add `search` and `warm` node roles to `NodeRole`

Add the `search` and `warm` node roles, correcting their descriptions
and version metadata against the OpenSearch server source.

Per `DiscoveryNodeRole.java`, the string `search` names two distinct
roles across versions, so this is not a simple rename:

- 2.4: `search` role added for searchable snapshots (#4689,
  opensearch-project/OpenSearch@c1272c1)
- 3.0: that role renamed `search` -> `warm` (#17573,
  opensearch-project/OpenSearch@1c86dd1)
- 3.0: a new, distinct `search` role introduced for search replicas
  (search-only shards, must not combine with other roles) (#17620,
  opensearch-project/OpenSearch@14d740f)

Signed-off-by: Matthias Oesterheld <matthias.oesterheld@graylog.com>
Signed-off-by: Sean Chittenden <sean.chittenden@crowdstrike.com>
Co-authored-by: Sean Chittenden <sean.chittenden@crowdstrike.com>

Author: moesterheld

CHANGELOG.md

@@ -43,6 +43,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added `allow_no_indices`, `ignore_unavailable`, and `ignore_throttled` query parameters to `create_pit` ([#1141](https://github.com/opensearch-project/opensearch-api-specification/pull/1141))
 - Added `query` to TermsLookup to support terms lookup by query
 - Added `mapper_type` and `mapper_settings` to `IngestionSource` index settings ([#1155](https://github.com/opensearch-project/opensearch-api-specification/pull/1155))
+- Added `search` and `warm` node roles to `NodeRole`, and modeled the pre-3.0 `search` role (renamed to `warm` in 3.0) as a version-scoped branch ([#1006](https://github.com/opensearch-project/opensearch-api-specification/pull/1006))
 
 ### Deprecated
 - Marked the plural `_aliases` URL forms of `put_alias` and `delete_alias` as deprecated; the singular `_alias` form is the canonical path ([#1131](https://github.com/opensearch-project/opensearch-api-specification/pull/1131))

spec/schemas/_common.yaml

@@ -2558,6 +2558,19 @@ components:
           const: cluster_manager
           description: The node can act as a cluster manager.
           x-version-added: '2.0'
+        - type: string
+          const: search
+          description: The node was dedicated to provide search capability for searchable snapshots. Renamed to `warm` in 3.0.
+          x-version-added: '2.4'
+          x-version-removed: '3.0'
+        - type: string
+          const: search
+          description: The node can host search replicas (search-only shards). This role must not be combined with any other role on a node. Introduced in 3.0; not to be confused with the pre-3.0 `search` role that was renamed to `warm`.
+          x-version-added: '3.0'
+        - type: string
+          const: warm
+          description: The node can hold warm indexes for searchable snapshots. Before 3.0 this role was named `search`.
+          x-version-added: '3.0'
     HttpHeaders:
       type: object
       description: The HTTP headers.