Address review comments

csi.proto

@@ -877,7 +877,7 @@ message GetVolumeResponse {
     // volume_health shows error conditions reported by the SP.
     // This field MUST be specified if the
     // VOLUME_HEALTH controller capability is supported.
-    VolumeHealth volume_health = 1 [(alpha_field) = true];
+    VolumeHealth volume_health = 1;
   }
 
   // This field is REQUIRED
@@ -1299,7 +1299,7 @@ message NodeGetVolumeStatsResponse {
   // This field is OPTIONAL.
   repeated VolumeUsage usage = 1;
   // This field is OPTIONAL.
-  VolumeHealth volume_health = 2 [(alpha_field) = true];
+  VolumeHealth volume_health = 2;
 }
 
 message VolumeUsage {
@@ -1328,32 +1328,40 @@ message VolumeHealth {
   option (alpha_message) = true;
 
   enum Condition {
-    // Volume health condition is unknown; If this is the initial
-    // report of volume health, treat it as healthy. If there was
-    // already a condition reported previously, treat unknown as
-    // unchanged from the previous condition.
+    // Volume health condition is unknown.
     UNKNOWN = 0;
     // Volume is accessible and no problems are detected. 
     HEALTHY = 1;
     // Volume is not accessible currently, but there's no reason to
     // expect data loss. Examples: power outage, network outage,
     // maintenance.
-    TEMPORARY_INACCESSIBLE = 2;
+    TEMPORARY_INACCESSIBLE = 10;
     // Volume is accessible currently, but is degraded. Data loss
-    // is unlikely as the storage system is rebuilding to fix the
+    // is unlikely as the storage system may be rebuilding to fix the
     // problem automatically. For example, a replica is lost on
     // the storage system but a spare is configured, and the storage
     // system is resyncing/reconstructing.
-    TEMPORARY_DEGRADED = 3;
+    TEMPORARY_DEGRADED = 20;
     // Volume is accessible currently, but a problem is detected that
     // could lead to eventual data loss. Examples: recoverable hardware
     // failure (i.e. the disk needs to be manually replaced by a human),
     // cooling failure, equipment significantly past end of life.
-    FAILURE_LIKELY = 4;
+    FAILURE_LIKELY = 30;
     // Volume is not accessible currently, and there is reason to
     // believe the outage may be permanent. Examples: unrecoverable
     // hardware failure, natural disasters, damage to equipment.
-    FATAL = 5;
+    FATAL = 40;
+  }
+
+  message VolumeHealthError {
+    // The code describing the health condition of the volume.
+    // This is an opaque field to CO.
+    // This field is OPTIONAL.
+    string code = 1;
+
+    // The error message associated with the above error code.
+    // This field is REQUIRED.
+    string message = 2;
   }
 
   // The level of the health condition of the volume.
@@ -1364,17 +1372,6 @@ message VolumeHealth {
   // the volume. This field is REQUIRED.
   repeated VolumeHealthError error = 2;
 }
-
-message VolumeHealthError {
-  // The error code describing the health condition of the volume.
-  // This is an opaque field to CO.
-  // This field is REQUIRED.
-  string error_code = 1;
-
-  // The error message associated with the above error code.
-  // This field is OPTIONAL.
-  string message = 2;
-}
 message NodeGetCapabilitiesRequest {
   // Intentionally empty.
 }