chart - Add configuration for extra volumes / volume mounts (#3042)

Adds configuration for additional volumes / volumeMounts to the Dendrite
pod to inject configuration / secrets outside of the chart's templates

### Pull Request Checklist

* [x] I have added Go unit tests or [Complement integration
tests](https://github.com/matrix-org/complement) for this PR _or_ I have
justified why this PR doesn't need tests - Helm chart changes
* [x] Pull request includes a [sign off below using a legally
identifiable
name](https://matrix-org.github.io/dendrite/development/contributing#sign-off)
_or_ I have already signed off privately

Signed-off-by: Rhea Danzey <rdanzey@element.io>

---------

Signed-off-by: Rhea Danzey <rdanzey@element.io>
Co-authored-by: Till <2353100+S7evinK@users.noreply.github.com>

[skip ci]

helm/dendrite/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v2
 name: dendrite
-version: "0.12.1"
+version: "0.12.2"
 appVersion: "0.12.0"
 description: Dendrite Matrix Homeserver
 type: application

helm/dendrite/templates/deployment.yaml

@@ -12,13 +12,6 @@ spec:
     matchLabels:
       {{- include "dendrite.selectorLabels" . | nindent 6 }}
   replicas: 1
-  template:
-    metadata:
-      labels:
-        {{- include "dendrite.selectorLabels" . | nindent 8 }}
-      annotations:
-        confighash: secret-{{ .Values.dendrite_config | toYaml | sha256sum | trunc 32 }}
-    spec:
   strategy:
     type: {{ $.Values.strategy.type }}
     {{- if eq $.Values.strategy.type "RollingUpdate" }}
@@ -26,6 +19,13 @@ spec:
       maxSurge: {{ $.Values.strategy.rollingUpdate.maxSurge }}
       maxUnavailable: {{ $.Values.strategy.rollingUpdate.maxUnavailable }}
     {{- end }}
+  template:
+    metadata:
+      labels:
+        {{- include "dendrite.selectorLabels" . | nindent 8 }}
+      annotations:
+        confighash: secret-{{ .Values.dendrite_config | toYaml | sha256sum | trunc 32 }}
+    spec:
       volumes:
       - name: {{ include "dendrite.fullname" . }}-conf-vol
         secret:
@@ -47,6 +47,9 @@ spec:
       - name: {{ include "dendrite.fullname" . }}-search
         persistentVolumeClaim:
           claimName: {{ default (print ( include "dendrite.fullname" . ) "-search-pvc") $.Values.persistence.search.existingClaim | quote }}
+      {{- with .Values.extraVolumes }}
+      {{ . | toYaml | nindent 6 }}
+      {{- end }}
       containers:
       - name: {{ .Chart.Name }}
         {{- include "image.name" . | nindent 8 }}
@@ -80,6 +83,9 @@ spec:
           name: {{ include "dendrite.fullname" . }}-jetstream
         - mountPath: {{ .Values.dendrite_config.sync_api.search.index_path }}
           name: {{ include "dendrite.fullname" . }}-search
+        {{- with .Values.extraVolumeMounts }}
+        {{ . | toYaml | nindent 8 }}
+        {{- end }}
         livenessProbe:
           initialDelaySeconds: 10
           periodSeconds: 10

helm/dendrite/values.yaml

@@ -43,6 +43,20 @@ persistence:
     # -- PVC Storage Request for the search volume
     capacity: "1Gi"
 
+# Add additional volumes to the Dendrite Pod
+extraVolumes: []
+# ex.
+# - name: extra-config
+#   secret:
+#     secretName: extra-config
+
+
+# Configure additional mount points volumes in the Dendrite Pod
+extraVolumeMounts: []
+# ex.
+# - mountPath: /etc/dendrite/extra-config
+#   name: extra-config
+
 strategy:
   # -- Strategy to use for rolling updates (e.g. Recreate, RollingUpdate)
   # If you are using ReadWriteOnce volumes, you should probably use Recreate