Add image layer reuse docs to metrics.md
@@ -38,6 +38,7 @@ Beside the [default golang based metrics][2], CRI-O provides the following addit
| `crio_image_pulls_by_name_skipped` | `name` | Counter | Bytes skipped by CRI-O image pulls by name. |
| `crio_image_pulls_successes` | `name` | Counter | Successful image pulls by image name |
| `crio_image_pulls_failures` | `name`, `error` | Counter | Failed image pulls by image name and their error category. |
+| `crio_image_layer_reuse` | `name` | Counter | Reused (not pulled) local image layer count by name. |
- Available CRI-O RPC's from the [gRPC API][3]: `Attach`, `ContainerStats`, `ContainerStatus`,
`CreateContainer`, `Exec`, `ExecSync`, `ImageFsInfo`, `ImageStatus`,
