[elasticsearch] Make persistent volumes optional

Certain node roles do not require any persistent data. Setting `persistence.enabled: false` will allow nodes to be created without persistent volumes. Fixes: #58 Fixes: #110
elastic · Crazybus · May 1, 2019 · May 1, 2019 · May 1, 2019 · 66d6db986352422e79e9ea76046dffc35812154a
commit 66d6db986352422e79e9ea76046dffc35812154a
diff --git a/elasticsearch/README.md b/elasticsearch/README.md
@@ -80,6 +80,7 @@ helm install --name elasticsearch elastic/elasticsearch --version 7.0.0-alpha1 -
 | `networkHost`              | Value for the [network.host Elasticsearch setting](https://www.elastic.co/guide/en/elasticsearch/reference/current/network.host.html)                                                                                                                                                                                      | `0.0.0.0`                                                                                                                 |
 | `volumeClaimTemplate`      | Configuration for the [volumeClaimTemplate for statefulsets](https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/#stable-storage). You will want to adjust the storage (default `30Gi`) and the `storageClassName` if you are using a different storage class                                            | `accessModes: [ "ReadWriteOnce" ]`<br>`resources.requests.storage: 30Gi`                                                  |
 | `persistence.annotations`  | Additional persistence annotations for the `volumeClaimTemplate`                                                                                                                                                                                                                                                           | `{}`                                                                                                                      |
+| `persistence.enabled`      | Enables a persistent volume for Elasticsearch data. Can be disabled for nodes that only have [roles](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html) which don't require persistent data.                                                                                               | `true`                                                                                                                    |
 | `antiAffinityTopologyKey`  | The [anti-affinity topology key](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity). By default this will prevent multiple Elasticsearch nodes from running on the same Kubernetes node                                                                                        | `kubernetes.io/hostname`                                                                                                  |
 | `antiAffinity`             | Setting this to hard enforces the [anti-affinity rules](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity). If it is set to soft it will be done "best effort". Other values will be ignored.                                                                                  | `hard`                                                                                                                    |
 | `nodeAffinity`             | Value for the [node affinity settings](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#node-affinity-beta-feature)                                                                                                                                                                                      | `{}`                                                                                                                      |

diff --git a/elasticsearch/examples/migration/client.yml b/elasticsearch/examples/migration/client.yml
@@ -18,3 +18,6 @@ volumeClaimTemplate:
   resources:
     requests:
       storage: 1Gi # Currently needed till pvcs are made optional
+
+persistence:
+  enabled: false
diff --git a/elasticsearch/templates/statefulset.yaml b/elasticsearch/templates/statefulset.yaml
@@ -17,6 +17,7 @@ spec:
   podManagementPolicy: {{ .Values.podManagementPolicy }}
   updateStrategy:
     type: {{ .Values.updateStrategy }}
+  {{- if .Values.persistence.enabled }}
   volumeClaimTemplates:
   - metadata:
       name: {{ template "uname" . }}
@@ -26,6 +27,7 @@ spec:
     {{- end }}
     spec:
 {{ toYaml .Values.volumeClaimTemplate | indent 6 }}
+  {{- end }}
   template:
     metadata:
       name: "{{ template "uname" . }}"
@@ -195,8 +197,10 @@ spec:
 {{ toYaml .Values.extraEnvs | indent 10 }}
 {{- end }}
         volumeMounts:
+          {{- if .Values.persistence.enabled }}
           - name: "{{ template "uname" . }}"
             mountPath: /usr/share/elasticsearch/data
+          {{- end }}
           {{- range .Values.secretMounts }}
           - name: {{ .name }}
             mountPath: {{ .path }}

diff --git a/elasticsearch/tests/elasticsearch_test.py b/elasticsearch/tests/elasticsearch_test.py
@@ -544,3 +544,12 @@ def test_adding_in_es_config():
     assert {'mountPath': '/usr/share/elasticsearch/config/log4j2.properties', 'name': 'esconfig', 'subPath': 'log4j2.properties'} in s['containers'][0]['volumeMounts']
 
     assert 'configchecksum' in r['statefulset'][uname]['spec']['template']['metadata']['annotations']
+
+def test_dont_add_data_volume_when_persistance_is_disabled():
+    config = '''
+persistence:
+  enabled: false
+'''
+    r = helm_template(config)
+    assert 'volumeClaimTemplates' not in r['statefulset'][uname]['spec']
+    assert r['statefulset'][uname]['spec']['template']['spec']['containers'][0]['volumeMounts'] == None
diff --git a/elasticsearch/values.yaml b/elasticsearch/values.yaml
@@ -76,6 +76,7 @@ volumeClaimTemplate:
       storage: 30Gi
 
 persistence:
+  enabled: true
   annotations: {}
 
 extraVolumes: []