NATS Server¶

The nats probe monitors a NATS Server via its HTTP management API (/varz, /routez, /jsz), reporting connections, subscriptions, message throughput, cluster routes and JetStream stream and consumer health. No external dependencies — uses the stdlib HTTP client.

Quick start¶

# probes.d/20-nats.yaml — each file under probes.d/ is a YAML array of probes
- name: nats
  type: nats
  params:
    endpoint: http://localhost:8222

Parameters¶

Parameter	Must set	Default	Description
`endpoint`	In practice	`http://localhost:8222`	Base URL of the NATS monitoring HTTP API. Example: `http://nats.example.com:8222`
`interval`	No	`60`	Seconds between collections
`instance_name`	No	-	Stable identity of this server instead of the server id it reports

Metrics¶

Metric	Unit	Description
`senhub.nats.up`	1	1 when `/varz` responds with HTTP 200
`nats.connections.count`	{connection}	Current active client connections
`nats.connections.total`	{connection}	Total connections since server start
`nats.subscriptions.count`	{subscription}	Active subscriptions
`nats.messages.in`	{message}	Messages received since start
`nats.messages.out`	{message}	Messages sent to subscribers since start
`nats.bytes.in`	By	Bytes received since start
`nats.bytes.out`	By	Bytes sent since start
`nats.slow_consumers`	{consumer}	Connections flagged as slow consumers
`nats.routes.count`	{connection}	Active cluster route connections
`nats.jetstream.streams`	{stream}	JetStream stream count
`nats.jetstream.consumers`	{consumer}	JetStream consumer count
`nats.jetstream.messages`	{message}	Messages stored in JetStream
`nats.jetstream.storage`	By	Bytes stored in JetStream

Operational notes¶

The management HTTP API is separate from the NATS client port (4222). Ensure it is enabled in the NATS server configuration: http: 8222 or http_port: 8222.
JetStream metrics are only emitted when JetStream is enabled on the server.

Metric reference¶

Every metric this probe can emit. Metric is the OpenTelemetry name the OTLP, Prometheus and Zabbix outputs derive theirs from. Name is what a Nagios check and the API metrics= filter match. PRTG channel is the label PRTG shows, placeholders filled from the series' tags.

Metric	Name	PRTG channel	Unit	Description
`senhub.nats.up`	`senhub.nats.up`	NATS Server Up	#	1 when the NATS management API (/varz) responds with HTTP 200
`nats.connections.count`	`nats.connections.count`	NATS Current Connections	#	Number of currently active client connections
`nats.connections.total`	`nats.connections.total`	NATS Total Connections	#	Total number of client connections since server start (monotonic counter)
`nats.subscriptions.count`	`nats.subscriptions.count`	NATS Active Subscriptions	#	Number of active subscriptions across all clients
`nats.messages.in`	`nats.messages.in`	NATS Messages In	#	Total number of messages received by the server since start
`nats.messages.out`	`nats.messages.out`	NATS Messages Out	#	Total number of messages sent by the server since start
`nats.bytes.in`	`nats.bytes.in`	NATS Bytes In	B	Total bytes received by the server since start
`nats.bytes.out`	`nats.bytes.out`	NATS Bytes Out	B	Total bytes sent by the server since start
`nats.slow_consumers`	`nats.slow_consumers`	NATS Slow Consumers	#	Number of slow consumer events detected since server start
`nats.routes.count`	`nats.routes.count`	NATS Cluster Routes	#	Number of active cluster routes (server-to-server connections)
`nats.jetstream.streams`	`nats.jetstream.streams`	NATS JetStream Streams	#	Number of JetStream streams (present only when JetStream is enabled)
`nats.jetstream.consumers`	`nats.jetstream.consumers`	NATS JetStream Consumers	#	Number of JetStream consumers across all streams
`nats.jetstream.messages`	`nats.jetstream.messages`	NATS JetStream Messages	#	Total number of messages stored in JetStream across all streams
`nats.jetstream.storage`	`nats.jetstream.storage`	NATS JetStream Storage	B	Total bytes stored in JetStream across all streams