Add readme to grafana-dashboards dir

grafana-dashboards/README.md

@@ -0,0 +1,21 @@
+# About these grafana dashboard files
+
+These are dashboard definitions as jsonnet templates. They are deployed using a
+Python script from https://github.com/jupyterhub/grafana-dashboard, which can be
+done via the deployer command:
+
+```bash
+deployer grafana deploy-dashboards $CLUSTER_NAME
+```
+
+Running this command has a pre-requisite that you have jsonnet installed,
+specifically the jsonnet binary built using golang called go-jsonnet.
+
+To just render the jsonnet templates, which is relevant during development, you
+can:
+
+1. Clone https://github.com/jupyterhub/grafana-dashboard somewhere
+2. Go to that folder, and then run something like:
+   ```bash
+   jsonnet -J vendor /some/path/2i2c-org/infrastructure/grafana-dashboards/cloud-cost-aws.jsonnet
+   ```

grafana-dashboards/cloud-cost-aws.jsonnet

@@ -93,6 +93,11 @@ local totalDailyCostsPerComponentAndHub =
 
 
 // grafonnet ref: https://grafana.github.io/grafonnet/API/dashboard/index.html
+//
+// A dashboard description can be provided, but isn't used much it seems, due to
+// that we aren't providing one atm.
+// See https://community.grafana.com/t/dashboard-description-is-it-used-anywhere/53273.
+//
 dashboard.new("Cloud cost attribution")
 + dashboard.withUid("cloud-cost-aws")
 + dashboard.withTimezone("utc")