VOL-2044 - allow a default image tag to be set in values

Change-Id: I538a521a58862b1259a80d4d568daa0b927074fa
diff --git a/voltha/Chart.yaml b/voltha/Chart.yaml
index 7dc328a..467e848 100644
--- a/voltha/Chart.yaml
+++ b/voltha/Chart.yaml
@@ -17,7 +17,7 @@
 description: A Helm chart for Voltha based on K8S resources in Voltha project
 icon: https://guide.opencord.org/logos/cord.svg
 
-version: 2.1.9
+version: 2.1.10
 
 # appVersion is 2 because this chart contains multiple 2.x images that may have
 # different individual image versions.
diff --git a/voltha/values.yaml b/voltha/values.yaml
index 07760d3..7b6a6bd 100644
--- a/voltha/values.yaml
+++ b/voltha/values.yaml
@@ -17,11 +17,14 @@
 private_etcd_cluster: true
 private_kafka_cluster: true
 
-# Default overrides
+# Default Values
+# The following are the default values used for every container in the
+# template.
 defaults:
   log_level: "ERROR"
   image_registry: ''
   image_org: "voltha/"
+  image_tag: ~
   image_pullPolicy: "Always"
   rw_core:
     timeout: "8000"
@@ -90,36 +93,36 @@
   cli:
     registry: '{{ .Values.defaults.image_registry }}'
     repository: '{{ .Values.defaults.image_org }}voltha-cli'
-    tag: '2.1.3'
+    tag: '{{ if hasKey .Values.defaults "image_tag" }}{{ .Values.defaults.image_tag }}{{ else }}2.1.3{{ end }}'
     pullPolicy: '{{ .Values.defaults.image_pullPolicy }}'
 
   ofagent:
     registry: '{{ .Values.defaults.image_registry }}'
     repository: '{{ .Values.defaults.image_org }}voltha-ofagent'
-    tag: '2.1.3'
+    tag: '{{ if hasKey .Values.defaults "image_tag" }}{{ .Values.defaults.image_tag }}{{ else }}2.1.3{{ end }}'
     pullPolicy: '{{ .Values.defaults.image_pullPolicy }}'
 
   ro_core:
     registry: '{{ .Values.defaults.image_registry }}'
     repository: '{{ .Values.defaults.image_org }}voltha-ro-core'
-    tag: '2.1.3'
+    tag: '{{ if hasKey .Values.defaults "image_tag" }}{{ .Values.defaults.image_tag }}{{ else }}2.1.3{{ end }}'
     pullPolicy: '{{ .Values.defaults.image_pullPolicy }}'
 
   rw_core:
     registry: '{{ .Values.defaults.image_registry }}'
     repository: '{{ .Values.defaults.image_org }}voltha-rw-core'
-    tag: '2.1.3'
+    tag: '{{ if hasKey .Values.defaults "image_tag" }}{{ .Values.defaults.image_tag }}{{ else }}2.1.3{{ end }}'
     pullPolicy: '{{ .Values.defaults.image_pullPolicy }}'
 
   afrouter:
     registry: '{{ .Values.defaults.image_registry }}'
     repository: '{{ .Values.defaults.image_org }}voltha-afrouter'
-    tag: '2.2.0'
+    tag: '{{ if hasKey .Values.defaults "image_tag" }}{{ .Values.defaults.image_tag }}{{ else }}2.2.0{{ end }}'
     pullPolicy: '{{ .Values.defaults.image_pullPolicy }}'
 
   afrouterd:
     registry: '{{ .Values.defaults.image_registry }}'
     repository: '{{ .Values.defaults.image_org }}voltha-afrouterd'
-    tag: '2.2.0'
+    tag: '{{ if hasKey .Values.defaults "image_tag" }}{{ .Values.defaults.image_tag }}{{ else }}2.2.0{{ end }}'
     pullPolicy: '{{ .Values.defaults.image_pullPolicy }}'
     restartPolicy: 'Always'