Update docs/configuring-playbook-prometheus-grafana.md

docs/configuring-playbook-prometheus-grafana.md

@@ -17,22 +17,26 @@ When setting, replace `example.com` with your own.
 
 ## Adjusting the playbook configuration — Prometheus
 
-Prometheus is an open-source systems monitoring and alerting toolkit. To enable it, add the following configuration to your `inventory/host_vars/matrix.example.com/vars.yml` file:
+Prometheus is an open-source systems monitoring and alerting toolkit. It is a time series database, which holds all the data we're going to talk about.
+
+To enable it, add the following configuration to your `inventory/host_vars/matrix.example.com/vars.yml` file:
 
 ```yaml
 prometheus_enabled: true
-
-# Uncomment to enable Node Exporter.
-# prometheus_node_exporter_enabled: true
 ```
 
-Name | Description
------|----------
-`prometheus_enabled`|[Prometheus](https://prometheus.io) is a time series database. It holds all the data we're going to talk about.
-`prometheus_node_exporter_enabled`|[Node Exporter](https://prometheus.io/docs/guides/node-exporter/) is an addon of sorts to Prometheus that collects generic system information such as CPU, memory, filesystem, and even system temperatures.
-
 **Note**: the retention policy of Prometheus metrics is [15 days by default](https://prometheus.io/docs/prometheus/latest/storage/#operational-aspects). Older data gets deleted automatically.
 
+### Enable metrics and graphs for generic system information (optional)
+
+You can enable the [Node Exporter](https://prometheus.io/docs/guides/node-exporter/), an addon of sorts to Prometheus that collects generic system information such as CPU, memory, filesystem, and even system temperatures.
+
+To enable it, add the following configuration to your `vars.yml` file:
+
+```yaml
+prometheus_node_exporter_enabled: true
+```
+
 ### Enable metrics and graphs for Postgres (optional)
 
 Expanding on the metrics exposed by the Synapse exporter and the Node exporter, the playbook can also install and configure the [PostgreSQL Server Exporter](https://github.com/prometheus-community/postgres_exporter) that exposes more detailed information about what's happening on your Postgres database.
@@ -158,8 +162,6 @@ Name | Description
 `matrix_metrics_exposure_enabled`|Set this to `true` to **enable metrics exposure for all services** on `https://matrix.example.com/metrics/*`. If you think this is too much, refer to the helpful (but nonexhaustive) list of individual `matrix_SERVICE_metrics_proxying_enabled` (or similar) variables below for exposing metrics on a per-service basis.
 `matrix_metrics_exposure_http_basic_auth_enabled`|Set this to `true` to protect all `https://matrix.example.com/metrics/*` endpoints with [Basic Authentication](https://en.wikipedia.org/wiki/Basic_access_authentication) (see the other variables below for supplying the actual credentials). When enabled, all endpoints beneath `/metrics` will be protected with the same credentials.
 `matrix_metrics_exposure_http_basic_auth_users`|Set this to the Basic Authentication credentials (raw `htpasswd` file content) used to protect `/metrics/*`. This htpasswd-file needs to be generated with the `htpasswd` tool and can include multiple username/password pairs.
-`matrix_synapse_metrics_enabled`|Set this to `true` to make Synapse expose metrics (locally, on the container network).
-`matrix_synapse_metrics_proxying_enabled`|Set this to `true` to expose Synapse's metrics on `https://matrix.example.com/metrics/synapse/main-process` and `https://matrix.example.com/metrics/synapse/worker/TYPE-ID`. Read [below](#collecting-synapse-worker-metrics-to-an-external-prometheus-server) if you're running a Synapse worker setup (`matrix_synapse_workers_enabled: true`). To password-protect the metrics, see `matrix_metrics_exposure_http_basic_auth_users` above.
 `prometheus_node_exporter_enabled`|Set this to `true` to enable the node (general system stats) exporter (locally, on the container network).
 `prometheus_node_exporter_container_labels_traefik_enabled`|Set this to `true` to expose the node (general system stats) metrics on `https://matrix.example.com/metrics/node-exporter`. To password-protect the metrics, see `matrix_metrics_exposure_http_basic_auth_users` above.
 `prometheus_postgres_exporter_enabled`|Set this to `true` to enable the [Postgres exporter](#enable-metrics-and-graphs-for-postgres-optional) (locally, on the container network).
@@ -169,7 +171,10 @@ Name | Description
 `matrix_hookshot_metrics_enabled`|Set this to `true` to make [Hookshot](configuring-playbook-bridge-hookshot.md) expose metrics (locally, on the container network).
 `matrix_hookshot_metrics_proxying_enabled`|Set this to `true` to expose the [Hookshot](configuring-playbook-bridge-hookshot.md) metrics on `https://matrix.example.com/metrics/hookshot`. To password-protect the metrics, see `matrix_metrics_exposure_http_basic_auth_users` above.
 `matrix_SERVICE_metrics_proxying_enabled`|Various other services/roles may provide similar `_metrics_enabled` and `_metrics_proxying_enabled` variables for exposing their metrics. Refer to each role for details. To password-protect the metrics, see `matrix_metrics_exposure_http_basic_auth_users` above or `matrix_SERVICE_container_labels_metrics_middleware_basic_auth_enabled`/`matrix_SERVICE_container_labels_metrics_middleware_basic_auth_users` variables provided by each role.
+`matrix_synapse_metrics_enabled`|Set this to `true` to make Synapse expose metrics (locally, on the container network).
+`matrix_synapse_metrics_proxying_enabled`|Set this to `true` to expose Synapse's metrics on `https://matrix.example.com/metrics/synapse/main-process` and `https://matrix.example.com/metrics/synapse/worker/TYPE-ID`. Read [below](#collecting-synapse-worker-metrics-to-an-external-prometheus-server) if you're running a Synapse worker setup (`matrix_synapse_workers_enabled: true`). To password-protect the metrics, see `matrix_metrics_exposure_http_basic_auth_users` above.
 `matrix_media_repo_metrics_enabled`|Set this to `true` to make media-repo expose metrics (locally, on the container network).
+`matrix_media_repo_metrics_proxying_enabled`|Set this to `true` to expose media-repo's metrics on `https://matrix.example.com/metrics/matrix-media-repo`.
 
 ### Collecting Synapse worker metrics to an external Prometheus server