[stable/logstash] Make LS_JAVA_OPTS configurable (#12311)

Make LS_JAVA_OPTS environment variable configurable as logstashJavaOpts in values.yaml. It could be passed as environment varibles in the config block as well, but given its importance, a user will be most probably configue java heap size if he is configuring the resource requests / limits
and this commit makes it more easy to do so via LS_JAVA_OPTS.

Signed-off-by: Abhishek Jaisingh <abhi2254015@gmail.com>

stable/logstash/Chart.yaml

@@ -3,7 +3,7 @@ description: Logstash is an open source, server-side data processing pipeline
 icon: https://www.elastic.co/assets/blt86e4472872eed314/logo-elastic-logstash-lt.svg
 home: https://www.elastic.co/products/logstash
 name: logstash
-version: 1.7.0
+version: 1.8.0
 appVersion: 6.7.0
 sources:
 - https://www.docker.elastic.co

stable/logstash/README.md

@@ -90,6 +90,7 @@ The following table lists the configurable parameters of the chart and its defau
 | `ingress.path`                  | Ingress path                                       | `/`                                              |
 | `ingress.hosts`                 | Ingress accepted hostnames                         | `["logstash.cluster.local"]`                     |
 | `ingress.tls`                   | Ingress TLS configuration                          | `[]`                                             |
+| `logstashJavaOpts`              | Java options for logstash like heap size           | `"-Xmx1g -Xms1g"`                                |
 | `resources`                     | Pod resource requests & limits                     | `{}`                                             |
 | `priorityClassName`             | priorityClassName                                  | `nil`                                            |
 | `nodeSelector`                  | Node selector                                      | `{}`                                             |

stable/logstash/templates/statefulset.yaml

@@ -72,6 +72,9 @@ spec:
               value: {{ .Values.elasticsearch.host | quote }}
             - name: ELASTICSEARCH_PORT
               value: {{ .Values.elasticsearch.port | quote }}
+            # Logstash Java Options
+            - name: LS_JAVA_OPTS
+              value: {{ .Values.logstashJavaOpts }}
             ## Additional env vars
           {{- range $key, $value := .Values.config }}
             - name: {{ $key | upper | replace "." "_" }}

stable/logstash/values.yaml

@@ -72,6 +72,9 @@ ingress:
   #    hosts:
   #      - logstash.cluster.local
 
+# set java options like heap size
+logstashJavaOpts: "-Xmx1g -Xms1g"
+
 resources: {}
   # We usually recommend not to specify default resources and to leave this as a conscious
   # choice for the user. This also increases chances charts run on environments with little