[elasticsearch] use new node.roles settings (#1186)

* [elasticsearch] use new node.roles settings

This commit update Elasticsearch chart to use the new node.roles
settings introduced in elastic/elasticsearch#54998.

* [elasticsearch] update doc

* [elasticsearch] update examples

* add link to roles doc

* add workaround for coordinating node

* update roles list

* fixup! update roles list

* remove data_frozen from default roles

this is needed because `data_frozen` role doesn't exist in Elasticsearch < 7.12.0

* fixup! remove data_frozen from default roles

Author: jmlrt

elasticsearch/README.md

@@ -154,7 +154,7 @@ support multiple versions with minimal changes.
 | `readinessProbe`                   | Configuration fields for the readiness [probe][]                                                                                                                                                                                                                                                                  | see [values.yaml][]                              |
 | `replicas`                         | Kubernetes replica count for the StatefulSet (i.e. how many pods)                                                                                                                                                                                                                                                 | `3`                                              |
 | `resources`                        | Allows you to set the [resources][] for the StatefulSet                                                                                                                                                                                                                                                           | see [values.yaml][]                              |
-| `roles`                            | A hash map with the specific [roles][] for the `nodeGroup`                                                                                                                                                                                                                                                        | see [values.yaml][]                              |
+| `roles`                            | A list with the specific [roles][] for the `nodeGroup`                                                                                                                                                                                                                                                            | see [values.yaml][]                              |
 | `schedulerName`                    | Name of the [alternate scheduler][]                                                                                                                                                                                                                                                                               | `""`                                             |
 | `secretMounts`                     | Allows you easily mount a secret as a file inside the StatefulSet. Useful for mounting certificates and other secrets. See [values.yaml][] for an example                                                                                                                                                         | `[]`                                             |
 | `securityContext`                  | Allows you to set the [securityContext][] for the container                                                                                                                                                                                                                                                       | see [values.yaml][]                              |
@@ -212,8 +212,27 @@ while they share the same `clusterName` value.
 
 For each Helm release, the nodes types can then be defined using `roles` value.
 
-An example of Elasticsearch cluster using 2 different Helm releases for master
-and data nodes can be found in [examples/multi][].
+An example of Elasticsearch cluster using 2 different Helm releases for master,
+data and coordinating nodes can be found in [examples/multi][].
+
+#### Coordinating nodes
+
+Every node is implicitly a coordinating node. This means that a node that has an
+explicit empty list of roles will only act as a coordinating node.
+
+When deploying coordinating-only node with Elasticsearch chart, it is required
+to define the empty list of roles in both `roles` value and `node.roles`
+settings:
+
+```yaml
+roles: []
+
+esConfig:
+  elasticsearch.yml: |
+    node.roles: []
+```
+
+More details in [#1186 (comment)][]
 
 #### Clustering and Node Discovery
 
@@ -380,6 +399,7 @@ about our development and testing process.
 
 [7.x]: https://github.com/elastic/helm-charts/releases
 [#63]: https://github.com/elastic/helm-charts/issues/63
+[#1186 (comment)]: https://github.com/elastic/helm-charts/pull/1186#discussion_r631166442
 [7.9.2]: https://github.com/elastic/helm-charts/blob/7.9.2/elasticsearch/README.md
 [BREAKING_CHANGES.md]: https://github.com/elastic/helm-charts/blob/master/BREAKING_CHANGES.md
 [CHANGELOG.md]: https://github.com/elastic/helm-charts/blob/master/CHANGELOG.md

elasticsearch/templates/_helpers.tpl

@@ -51,6 +51,12 @@ We truncate at 63 chars because some Kubernetes name fields are limited to this
   {{- end -}}
 {{- end -}}
 
+{{- define "elasticsearch.roles" -}}
+{{- range $.Values.roles -}}
+{{ . }},
+{{- end -}}
+{{- end -}}
+
 {{- define "elasticsearch.esMajorVersion" -}}
 {{- if .Values.esMajorVersion -}}
 {{ .Values.esMajorVersion }}

elasticsearch/templates/statefulset.yaml

@@ -295,15 +295,12 @@ spec:
             valueFrom:
               fieldRef:
                 fieldPath: metadata.name
-          {{- if eq .Values.roles.master "true" }}
-          {{- if ge (int (include "elasticsearch.esMajorVersion" .)) 7 }}
+          {{- if has "master" .Values.roles }}
           - name: cluster.initial_master_nodes
             value: "{{ template "elasticsearch.endpoints" . }}"
-          {{- else }}
-          - name: discovery.zen.minimum_master_nodes
-            value: "{{ .Values.minimumMasterNodes }}"
-          {{- end }}
           {{- end }}
+          - name: node.roles
+            value: "{{ template "elasticsearch.roles" . }}"
           {{- if lt (int (include "elasticsearch.esMajorVersion" .)) 7 }}
           - name: discovery.zen.ping.unicast.hosts
             value: "{{ template "elasticsearch.masterService" . }}-headless"
@@ -319,10 +316,6 @@ spec:
           - name: ES_JAVA_OPTS
             value: "{{ .Values.esJavaOpts }}"
           {{- end }}
-          {{- range $role, $enabled := .Values.roles }}
-          - name: node.{{ $role }}
-            value: "{{ $enabled }}"
-          {{- end }}
 {{- if .Values.extraEnvs }}
 {{ toYaml .Values.extraEnvs | indent 10 }}
 {{- end }}

elasticsearch/values.yaml

@@ -7,13 +7,19 @@ nodeGroup: "master"
 masterService: ""
 
 # Elasticsearch roles that will be applied to this nodeGroup
-# These will be set as environment variables. E.g. node.master=true
+# These will be set as environment variables. E.g. node.roles=master
+# https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html#node-roles
 roles:
-  master: "true"
-  ingest: "true"
-  data: "true"
-  remote_cluster_client: "true"
-  ml: "true"
+  - master
+  - data
+  - data_content
+  - data_hot
+  - data_warm
+  - data_cold
+  - ingest
+  - ml
+  - remote_cluster_client
+  - transform
 
 replicas: 3
 minimumMasterNodes: 2