Add PURE as a Cinder backend

In this Patchset, Cinder configuration is added to values_overrides
for supporting PURE as one possible Cinder block storage backend.

Please note: updated images are needed for Cinder and Nova to
include package purestorage for the support of pure backend.

Change-Id: Ic0f1116045d74ec624449fbaf92858ccf8d4d936

cinder/values_overrides/backend_pure.yaml

@@ -0,0 +1,27 @@
+# NOTE: In order for below code to work, package "purestorage"
+# needs to be built into Cinder and Nova images.
+
+pod:
+  useHostNetwork:
+    volume: true
+  security_context:
+    cinder_volume:
+      container:
+        cinder_volume:
+          readOnlyRootFilesystem: true
+          privileged: true
+conf:
+  cinder:
+    DEFAULT:
+      enabled_backends: "rbd1,PURE"
+  backends:
+    PURE:
+      pure_eradicate_on_delete: true
+      volume_backend_name: PURE_BE
+      # NOTE: Replace below pure-api-token-value with the real token value
+      pure_api_token: pure-api-token-value
+      volume_driver: cinder.volume.drivers.pure.PureISCSIDriver
+      use_multipath_for_image_xfer: true
+      # NOTE: Replace below 1.1.1.1 with the real ip value
+      san_ip: 1.1.1.1
+  enable_iscsi: true