add grafana dashboard

Signed-off-by: yeya24 <[email protected]>

docs/user_guide/monitoring.md

@@ -137,4 +137,13 @@ As for naming of metric and label, it is better to follow the best practice. We
 
 In order to monitor the over-all status of Dragonfly components, you may need to use other exporters. Prometheus itself has a huge ecosystem, including all kinds of exporters with different utilities. You can check [exporters](https://prometheus.io/docs/instrumenting/exporters/) for more information.
 
-If you want to monitor the io status and network traffic of supernodes, we recommend you to use [node_exporter](https://github.com/prometheus/node_exporter).
+If you want to monitor the io status and network traffic of supernodes, we recommend you to use [node_exporter](https://github.com/prometheus/node_exporter).
+
+### Use Grafana Dashboard
+
+With metrics exposed in supernode, we can view these metrics in Grafana dashboards now by configuring [Prometheus Datasource](https://grafana.com/docs/features/datasources/prometheus/) first.
+
+Example screenshots:
+
+
+You can also import this dashboard json file into Grafana or just import it from .