[k8s] Expose autoscaler prometheus metrics

Expose autoscaler prometheus metrics on pod
port/portName name metrics (8085).

task: 37574
story: 2006765

Change-Id: Ieedd0f60625eb5a5ce50a3b4e7344cae37c377bf
Signed-off-by: Diogo Guerra <diogo.filipe.tomas.guerra@cern.ch>

magnum/drivers/common/templates/kubernetes/fragments/enable-auto-scaling.sh

@@ -138,6 +138,10 @@ spec:
             - --scale-down-unneeded-time=10m
             - --scale-down-delay-after-failure=3m
             - --scale-down-delay-after-add=10m
+          ports:
+          - containerPort: 8085
+            name: metrics
+            protocol: TCP
           volumeMounts:
             - name: ca-bundle
               mountPath: /etc/kubernetes

releasenotes/notes/expose_autoscaler_metrics-0ea9c61660409efe.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    Expose autoscaler prometheus metrics on pod port metrics (8085).