fix(ceilometer): use payload.node for consistency

`host` is derived from the publisher id similar to `service`, which
might be a compute api node in lieu of the actual compute hype. The node
param under payload seems sticky to the hypervisor name, so defer to
that in the gnocchi resource definition...

base-helm-configs/ceilometer/ceilometer-helm-overrides.yaml

@@ -144,6 +144,8 @@ conf:
           fields: publisher_id.`split(., 1, 1)`
         service:
           fields: publisher_id.`split(., 0, -1)`
+        node:
+          fields: payload.node
         memory_mb:
           type: int
           fields: payload.memory_mb
@@ -853,7 +855,7 @@ conf:
           radosgw.containers.objects.size:
 
       - resource_type: instance
-        metrics:
+        metrics: &instance_metrics
           memory:
           memory.usage:
           memory.resident:
@@ -878,7 +880,7 @@ conf:
           perf.cache.references:
           perf.cache.misses:
         attributes:
-          host: resource_metadata.(instance_host|host)
+          host: resource_metadata.(node|instance_host|host)
           image_ref: resource_metadata.image_ref
           launched_at: resource_metadata.launched_at
           created_at: resource_metadata.created_at
@@ -892,7 +894,7 @@ conf:
         event_attributes:
           id: instance_id
           display_name: display_name
-          host: host
+          host: node
           availability_zone: availability_zone
           flavor_id: instance_type_id
           flavor_name: instance_type
@@ -903,39 +905,24 @@ conf:
           instance_disk: '{"=": {"instance_id": "%s"}}'
 
       - resource_type: instance
-        metrics: null
+        metrics:
+          <<: *instance_metrics
         attributes:
+          host: resource_metadata.(node|instance_host|host)
           image_ref: resource_metadata.image_ref
           display_name: resource_metadata.display_name
           flavor_id: resource_metadata.(instance_flavor_id|(flavor.id)|flavor_id)
           flavor_name: resource_metadata.(instance_type|(flavor.name)|flavor_name)
           server_group: resource_metadata.user_metadata.server_group
         event_update:
           - compute.instance.update
-        event_attributes:
-          id: instance_id
-          display_name: display_name
-          flavor_id: instance_type_id
-          flavor_name: instance_type
-          image_ref: image_ref
-
-      - resource_type: instance
-        metrics: null
-        attributes:
-          host: resource_metadata.(instance_host|host)
-          image_ref: resource_metadata.image_ref
-          display_name: resource_metadata.display_name
-          flavor_id: resource_metadata.(instance_flavor_id|(flavor.id)|flavor_id)
-          flavor_name: resource_metadata.(instance_type|(flavor.name)|flavor_name)
-          server_group: resource_metadata.user_metadata.server_group
-        event_update:
           - compute.instance.exists
           - compute.instance.resize_confirm.end
           - compute.instance.resize_revert.end
         event_attributes:
           id: instance_id
           display_name: display_name
-          host: host
+          host: node
           flavor_id: instance_type_id
           flavor_name: instance_type
           image_ref: image_ref