add docs

docs/index.rst

@@ -52,6 +52,7 @@ ABCI, Apps, Logging, Etc
    indexing-transactions.md
    how-to-read-logs.md
    running-in-production.md
+   metrics.md
 
 Research & Specification
 ------------------------

docs/metrics.md

@@ -0,0 +1,26 @@
+# Metrics
+
+Tendermint can serve metrics under `/metrics` RPC endpoint, which can be
+consumed by Prometheus server.
+
+This functionality is disabled by default. Set `monitoring=true` if your config
+to enable it.
+
+## List of available metrics
+
+| Name                                    | Type    | Description                                                                   |
+| --------------------------------------- | ------- | ----------------------------------------------------------------------------- |
+| consensus_height                        | Gauge   | Height of the chain                                                           |
+| consensus_validators                    | Gauge   | Number of validators                                                          |
+| consensus_validators_power              | Gauge   | Total voting power of all validators                                          |
+| consensus_missing_validators            | Gauge   | Number of validators who did not sign                                         |
+| consensus_missing_validators_power      | Gauge   | Total voting power of the missing validators                                  |
+| consensus_byzantine_validators          | Gauge   | Number of validators who tried to double sign                                 |
+| consensus_byzantine_validators_power    | Gauge   | Total voting power of the byzantine validators                                |
+| consensus_block_interval                | Timing  | Time between this and last block (Block.Header.Time)                          |
+| consensus_rounds                        | Gauge   | Number of rounds                                                              |
+| consensus_num_txs                       | Gauge   | Number of transactions                                                        |
+| mempool_size                            | Gauge   | Number of uncommitted transactions                                            |
+| consensus_total_txs                     | Gauge   | Total number of transactions committed                                        |
+| consensus_block_size                    | Gauge   | Block size in bytes                                                           |
+| p2p_peers                               | Gauge   | Number of peers node's connected to                                           |

node/node.go

@@ -111,7 +111,7 @@ func DefaultMetricsProvider() (*cs.Metrics, *p2p.Metrics, *mempl.Metrics) {
 			Validators: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
 				Subsystem: "consensus",
 				Name:      "validators",
-				Help:      "Number of validators who signed.",
+				Help:      "Number of validators.",
 			}, []string{}),
 			ValidatorsPower: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
 				Subsystem: "consensus",