Configure a MongoDB exporter to generate Prometheus metrics

Use the recommended Percona MongoDB Exporter to export MongoDB metrics in Prometheus format.

To configure a MongoDB exporter, complete the following steps:

Run the following command to start the Docker version of the exporter:

docker run -d -p 9216:9216 -p 17001:17001 percona/mongodb_exporter:0.39 --mongodb.uri=mongodb://mongodb:17001

Use MONGODB_USER and MONGODB_PASSWORD to pass credentials.
Alternatively, you can use the MongoDB exporter Prometheus community helm chart.

Request and error metrics

Metric Key Performance Indicator

Metric	Key Performance Indicator
`mongodb_op_counters_total`	Request Rate `rate(mongodb_op_counters_total[5m])`
`mongodb_op_counters_repl_total mongodb_mongod_op_counters_repl_total`	Request Rate `rate(…[5m])`
`mongodb_mongod_op_latencies_ops/latencies_total`	Latency Average `rate(mongodb_mongod_op_latencies_latency_total[5m])/rate(mongodb_mongod_op_latencies_ops_total[5m])`

mongodb_op_counters_total

Request Rate

rate(mongodb_op_counters_total[5m])

mongodb_op_counters_repl_total mongodb_mongod_op_counters_repl_total

Request Rate

rate(…[5m])

mongodb_mongod_op_latencies_ops/latencies_total

Latency Average

rate(mongodb_mongod_op_latencies_latency_total[5m])/rate(mongodb_mongod_op_latencies_ops_total[5m])

Resource metrics

Metric Key Performance Indicator

Metric	Key Performance Indicator
Connection Counts `mongodb_ss_connections`	Connection Usage `mongodb_ss_connections{conn_type=“current”}/ ignoring(conn_type)(mongodb_ss_connections{conn_type=“current”} + ignoring(conn_type) mongodb_ss_connections{conn_type=“available”})`

Connection Counts mongodb_ss_connections

Connection Usage

mongodb_ss_connections{conn_type=“current”}/ ignoring(conn_type)(mongodb_ss_connections{conn_type=“current”} + ignoring(conn_type) mongodb_ss_connections{conn_type=“available”})

Alerts

KPI	Alert
Request Rate	RequestRateAnomaly
Latency Average	LatencyAverageAnomaly, LatencyAverageBreach
Connection Usage	Saturation with a severity level of critical when utilization exceeds 90%

Failure alerts

Alert	Description
MongodbDown	Fires when Mongo DB is down
MongodbReplicaMemberUnhealthy	Fires when a replica in a replication set is unhealthy
MongodbReplicationLag	Fires when the replication lag of a secondary is more than a configured time duration. Severity is set to `warning` when lag > 60s and `critical` when lag > 240s.
MongodbReplicationHeadroom	Fires when the replication lag of a secondary is more than a configured time duration. Severity is set to `warning` when lag > 60s and `critical` when lag > 240s.
MongodbTooManyCursorsOpen	Fires when the number of open cursors is above a given threshold. By default, the threshold is set to `10000`. Severity is set to `warning`.
MongodbTooManyCursorTimeouts	Fires if the rate of cursor timeout is above a certain threshold. By default, the threshold is set to `100`. Severity is set to `warning`.
MongodbInternalErrors	Fires when the count of internal errors keeps growing for `5m`. Severity is set to `warning`.
MongodbUserErrors	Fires when the count of user errors keeps growing for `5m`. Severity is set to `warning.`
ReadRequestsQueueingUp	If the read queue keeps growing for `5m`. Severity is set to `warning`.
WriteRequestsQueueingUp	If the write queue keeps growing for `5m`. Severity is set to `warning.`