Added cluster/temp_cache_dir

When using Barbican with a large number of clusters, this option can
allow Magnum to cache the certificates locally to avoid hitting
the API excessively. It is enabled out of the box however since
we don't have that folder, it is not working.

Change-Id: I63cb35798b82460f7addd4ec719c157e2c1c4fd9

magnum/Chart.yaml

@@ -14,7 +14,7 @@ apiVersion: v1
 appVersion: v1.0.0
 description: OpenStack-Helm Magnum
 name: magnum
-version: 0.2.3
+version: 0.2.4
 home: https://docs.openstack.org/magnum/latest/
 icon: https://www.openstack.org/themes/openstack/images/project-mascots/Magnum/OpenStack_Project_Magnum_vertical.png
 sources:

magnum/templates/statefulset-conductor.yaml

@@ -108,6 +108,8 @@ spec:
               mountPath: /tmp/pod-shared
             - name: magnum-lock-path
               mountPath: {{ .Values.conf.magnum.oslo_concurrency.lock_path }}
+            - name: magnum-certificate-cache
+              mountPath: {{ .Values.conf.magnum.cluster.temp_cache_dir }}
 {{ if $mounts_magnum_conductor.volumeMounts }}{{ toYaml $mounts_magnum_conductor.volumeMounts | indent 12 }}{{ end }}
       volumes:
         - name: pod-tmp
@@ -126,5 +128,7 @@ spec:
             defaultMode: 0444
         - name: magnum-lock-path
           emptyDir: {}
+        - name: magnum-certificate-cache
+          emptyDir: {}
 {{ if $mounts_magnum_conductor.volumes }}{{ toYaml $mounts_magnum_conductor.volumes | indent 8 }}{{ end }}
 {{- end }}

magnum/values.yaml

@@ -115,6 +115,8 @@ conf:
     DEFAULT:
       log_config_append: /etc/magnum/logging.conf
       transport_url: null
+    cluster:
+      temp_cache_dir: /var/lib/magnum/certificate-cache
     oslo_messaging_notifications:
       driver: messaging
     oslo_concurrency:

releasenotes/notes/magnum.yaml

@@ -7,4 +7,5 @@ magnum:
   - 0.2.1 Use policies in yaml format
   - 0.2.2 Fix restarting of magnum-conductor pods
   - 0.2.3 Update htk requirements repo
+  - 0.2.4 Mount empty temp_cache_dir for performance
 ...