[elasticsearch] Add option to provide custom start/stop hooks

elasticsearch/README.md

@@ -106,6 +106,7 @@ helm install --name elasticsearch elastic/elasticsearch --version 7.2.0 --set im
 | `ingress`                  | Configurable [ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) to expose the Elasticsearch service. See [`values.yaml`](./values.yaml) for an example                                                                                                                                            | `enabled: false`                                                                                                          |
 | `schedulerName`            | Name of the [alternate scheduler](https://kubernetes.io/docs/tasks/administer-cluster/configure-multiple-schedulers/#specify-schedulers-for-pods)                                                                                                                                                                          | `nil`                                                                                                                     |
 | `masterTerminationFix`     | A workaround needed for Elasticsearch < 7.2.0 to prevent master status being lost during restarts [#63](https://github.com/elastic/helm-charts/issues/63)                                                                                                                                                                  | `false`                                                                                                                   |
+| `lifecycle`                 | Allows you to add lifecycle configuration. See [values.yaml](./values.yaml) for an example of the formatting.                                                                                                                           | `{}`                                                                                                                      |
 
 ## Try it out
 

elasticsearch/templates/configmap.yaml

@@ -1,5 +1,4 @@
 {{- if .Values.esConfig }}
----
 apiVersion: v1
 kind: ConfigMap
 metadata:

elasticsearch/templates/statefulset.yaml

@@ -276,3 +276,7 @@ spec:
         {{- end }}
       {{- end }}
       {{- end }}
+{{- if .Values.lifecycle }}
+        lifecycle:
+{{ toYaml .Values.lifecycle | indent 10 }}
+{{- end }}

elasticsearch/tests/elasticsearch_test.py

@@ -655,3 +655,20 @@ def test_master_termination_fixed_enabled():
 
     c = r['statefulset'][uname]['spec']['template']['spec']['containers'][1]
     assert c['name'] == 'elasticsearch-master-graceful-termination-handler'
+
+def test_lifecycle_hooks():
+    config = ''
+    r = helm_template(config)
+    c = r['statefulset'][uname]['spec']['template']['spec']['containers'][0]
+    assert 'lifecycle' not in c
+
+    config = '''
+    lifecycle:
+      preStop:
+        exec:
+          command: ["/bin/bash","/preStop"]
+    '''
+    r = helm_template(config)
+    c = r['statefulset'][uname]['spec']['template']['spec']['containers'][0]
+
+    assert c['lifecycle']['preStop']['exec']['command'] == ["/bin/bash","/preStop"]

elasticsearch/values.yaml

@@ -184,3 +184,11 @@ fullnameOverride: ""
 
 # https://github.com/elastic/helm-charts/issues/63
 masterTerminationFix: false
+
+lifecycle: {}
+  # preStop:
+  #   exec:
+  #     command: ["/bin/sh", "-c", "echo Hello from the postStart handler > /usr/share/message"]
+  # postStart:
+  #   exec:
+  #     command: ["/bin/sh", "-c", "echo Hello from the postStart handler > /usr/share/message"]