Document Grafana integration.

content/docs/visualization/grafana.md

+---
+title: Grafana
+sort_rank: 7
+---
+
+# Grafana support for Prometheus
+There is early support for querying Prometheus servers from [Grafana](http://grafana.org/).
+The Grafana data source for Prometheus currently lives in the
+[grafana-plugins](https://github.com/grafana/grafana-plugins) repository.
+
+The following shows an example Grafana dashboard which queries Prometheus for data:
+
+[![Grafana screenshot](/assets/grafana_prometheus.png)](/assets/grafana_prometheus.png)
+
+## Installing
+For general Grafana installation instructions, see the [official Grafana
+documentation](http://docs.grafana.org/installation/).
+
+To use the Prometheus data source with Grafana, copy the
+`datasources/prometheus` directory from the `grafana-plugins` repository to
+the `public/app/plugins/datasource` directory of your Grafana server.
+
+For example, on Linux, installing Grafana and the Prometheus data source could
+look like this:
+
+```bash-lang
+# Download and unpack Grafana from binary tar (adjust version as appropriate).
+curl -L -O https://grafanarel.s3.amazonaws.com/builds/grafana-2.0.2.linux-x64.tar.gz
+tar zxf grafana-2.0.2.linux-x64.tar.gz
+
+# Copy the Prometheus datasource from 'grafana-plugins' into Grafana.
+git clone https://github.com/grafana/grafana-plugins.git
+cp -a grafana-plugins/datasources/prometheus grafana-2.0.2/public/app/plugins/datasource/
+
+# Start Grafana.
+cd grafana-2.0.2/
+./bin/grafana-server web
+```
+
+## Using
+By default, Grafana will be listening on
+[http://localhost:3000](http://localhost:3000). The default login is "admin" /
+"admin".
+
+### Creating a Prometheus data source
+To create a Prometheus data source:
+
+1. Click on the Grafana logo to open the sidebar menu.
+2. Click on "Data Sources" in the sidebar.
+3. Click on "Add New".
+4. Select "Prometheus" as the type.
+5. Set the appropriate Prometheus server URL (for example, `http://localhost:9090/`)
+6. Adjust other data source settings as desired (for example, turning the proxy access off).
+7. Click "Add" to save the new data source.
+
+The following shows an example data source configuration:
+
+[![Data source configuration](/assets/grafana_configuring_datasource.png)](/assets/grafana_configuring_datasource.png)
+
+### Creating a Prometheus graph
+Follow the standard way of adding a new Grafana graph. Then:
+
+1. Click the graph title, then click "Edit".
+2. Under the "Metrics" tab, select your Prometheus data source (bottom right).
+3. Enter any Prometheus expression into the "Query" field, while using the "Metric" field to lookup metrics via autocompletion.
+4. To format the legend names of time series, use the "Legend format" input in a
+similar way to PromDash. For example, to show only the `method` and `status`
+labels of a returned query result, separated by a dash, you could use the
+legend format string `{{method}} - {{status}}`.
+5. Tune other graph settings until you have a working graph.
+
+The following shows an example Prometheus graph configuration:
+[![Prometheus graph creation](/assets/grafana_qps_graph.png)](/assets/grafana_qps_graph.png)