Monitoring
Monitoring NATS
To monitor the NATS messaging system, nats-server provides a lightweight HTTP server on a dedicated monitoring port. The monitoring server provides several endpoints, providing statistics and other information about the following:
All endpoints return a JSON object.
Note that info from these monitoring endpoints is also available through System services
The NATS monitoring endpoints support JSONP and CORS, making it easy to create single page monitoring web applications. Part of the NATS ecosystem is a tool called nats-top that visualizes data from these endpoints on the command line.
{% hint style="warning" %}
nats-server does not have authentication/authorization for the monitoring endpoint. When you plan to open your nats-server to the internet make sure to not expose the monitoring port as well. By default, monitoring binds to every interface 0.0.0.0 so consider setting monitoring to localhost or have appropriate firewall rules.
{% endhint %}
Enabling monitoring
Monitoring can be enabled in server configuration or as a server command-line option. The conventional port is 8222.
As server configuration:
As a command-line option:
Once the server is running using one of the two methods, go to http://localhost:8222 to browse the available endpoints detailed below.
Alternatively, if you have System account enabled, monitoring endpoints available as "System services"
Monitoring Endpoints
General Information (/varz)
The /varz endpoint returns general information about the server state and configuration.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
N/A
Example
https://demo.nats.io:8222/varz
Response
{
"server_id": "NACDVKFBUW4C4XA24OOT6L4MDP56MW76J5RJDFXG7HLABSB46DCMWCOW",
"version": "2.0.0",
"proto": 1,
"go": "go1.12",
"host": "0.0.0.0",
"port": 4222,
"max_connections": 65536,
"ping_interval": 120000000000,
"ping_max": 2,
"http_host": "0.0.0.0",
"http_port": 8222,
"https_port": 0,
"auth_timeout": 1,
"max_control_line": 4096,
"max_payload": 1048576,
"max_pending": 67108864,
"cluster": {},
"gateway": {},
"leaf": {},
"tls_timeout": 0.5,
"write_deadline": 2000000000,
"start": "2019-06-24T14:24:43.928582-07:00",
"now": "2019-06-24T14:24:46.894852-07:00",
"uptime": "2s",
"mem": 9617408,
"cores": 4,
"gomaxprocs": 4,
"cpu": 0,
"connections": 0,
"total_connections": 0,
"routes": 0,
"remotes": 0,
"leafnodes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"slow_consumers": 2,
"subscriptions": 0,
"http_req_stats": {
"/": 0,
"/connz": 0,
"/gatewayz": 0,
"/routez": 0,
"/subsz": 0,
"/varz": 1
},
"config_load_time": "2019-06-24T14:24:43.928582-07:00",
"slow_consumer_stats": {
"clients": 1,
"routes": 1,
"gateways": 0,
"leafs": 0
}
}
Connection Information (/connz)
The /connz endpoint reports more detailed information on current and recently closed connections. It uses a paging mechanism which defaults to 1024 connections.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| sort |
(see sort options) |
Sorts the results. Default is connection ID. |
| auth |
true, 1, false, 0 |
Include username. Default is false. |
| subs |
true, 1, false, 0 or detail |
Include subscriptions. Default is false. When set to detail a list with more detailed subscription information will be returned. |
| offset |
number > 0 |
Pagination offset. Default is 0. |
| limit |
number > 0 |
Number of results to return. Default is 1024. |
| cid |
number, valid id |
Return a connection by its id |
| state |
open, *closed, any |
Return connections of particular state. Default is open. |
| mqtt_client |
string |
Filter the connection with this MQTT client ID. |
The server will default to holding the last 10,000 closed connections.
Sort Options
| Option |
Sort by |
| cid |
Connection ID |
| start |
Connection start time, same as CID |
| subs |
Number of subscriptions |
| pending |
Amount of data in bytes waiting to be sent to client |
| msgs_to |
Number of messages sent |
| msgs_from |
Number of messages received |
| bytes_to |
Number of bytes sent |
| bytes_from |
Number of bytes received |
| last |
Last activity |
| idle |
Amount of inactivity |
| uptime |
Lifetime of the connection |
| stop |
Stop time for a closed connection |
| reason |
Reason for a closed connection |
| rtt |
Round trip time |
Examples
Get up to 1024 connections: https://demo.nats.io:8222/connz
Control limit and offset: https://demo.nats.io:8222/connz?limit=16\&offset=128.
Get closed connection information: https://demo.nats.io:8222/connz?state=closed.
You can also report detailed subscription information on a per connection basis using subs=1. For example: https://demo.nats.io:8222/connz?limit=1\&offset=1\&subs=1.
Response
{
"server_id": "NACDVKFBUW4C4XA24OOT6L4MDP56MW76J5RJDFXG7HLABSB46DCMWCOW",
"now": "2019-06-24T14:28:16.520365-07:00",
"num_connections": 2,
"total": 2,
"offset": 0,
"limit": 1024,
"connections": [
{
"cid": 5,
"kind": "Client",
"type": "nats",
"ip": "127.0.0.1",
"port": 62714,
"start": "2021-09-09T23:16:43.040862Z",
"last_activity": "2021-09-09T23:16:43.042364Z",
"rtt": "95µs",
"uptime": "5s",
"idle": "5s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 1,
"name": "NATS Benchmark",
"lang": "go",
"version": "1.12.1"
},
{
"cid": 6,
"kind": "Client",
"type": "nats",
"ip": "127.0.0.1",
"port": 62715,
"start": "2021-09-09T23:16:43.042557Z",
"last_activity": "2021-09-09T23:16:43.042811Z",
"rtt": "100µs",
"uptime": "5s",
"idle": "5s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 1,
"name": "NATS Benchmark",
"lang": "go",
"version": "1.12.1"
},
{
"cid": 7,
"kind": "Client",
"type": "mqtt",
"ip": "::1",
"port": 62718,
"start": "2021-09-09T23:16:45.391459Z",
"last_activity": "2021-09-09T23:16:45.395869Z",
"rtt": "0s",
"uptime": "2s",
"idle": "2s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 2,
"mqtt_client": "mqtt_sub"
}
]
}
Route Information (/routez)
The /routez endpoint reports information on active routes for a cluster. Routes are expected to be low, so there is no paging mechanism with this endpoint.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| subs |
true, 1, false, 0 or detail |
Include subscriptions. Default is false. When set to detail a list with more detailed subscription information will be returned. |
As noted above, the routez endpoint does support the subs argument from the /connz endpoint. For example: https://demo.nats.io:8222/routez?subs=1
Example
Response
{
"server_id": "NACDVKFBUW4C4XA24OOT6L4MDP56MW76J5RJDFXG7HLABSB46DCMWCOW",
"now": "2019-06-24T14:29:16.046656-07:00",
"num_routes": 1,
"routes": [
{
"rid": 1,
"remote_id": "de475c0041418afc799bccf0fdd61b47",
"did_solicit": true,
"ip": "127.0.0.1",
"port": 61791,
"pending_size": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 0
}
]
}
Gateway Information (/gatewayz)
The /gatewayz endpoint reports information about gateways used to create a NATS supercluster. Like routes, the number of gateways are expected to be low, so there is no paging mechanism with this endpoint.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| accs |
true, 1, false, 0 |
Include account information. Default is false. |
| gw_name |
string |
Return only remote gateways with this name. |
| acc_name |
string |
Limit the list of accounts to this account name. |
Examples
Response
{
"server_id": "NANVBOU62MDUWTXWRQ5KH3PSMYNCHCEUHQV3TW3YH7WZLS7FMJE6END6",
"now": "2019-07-24T18:02:55.597398-06:00",
"name": "region1",
"host": "2601:283:4601:1350:1895:efda:2010:95a1",
"port": 4501,
"outbound_gateways": {
"region2": {
"configured": true,
"connection": {
"cid": 7,
"ip": "127.0.0.1",
"port": 5500,
"start": "2019-07-24T18:02:48.765621-06:00",
"last_activity": "2019-07-24T18:02:48.765621-06:00",
"uptime": "6s",
"idle": "6s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 0,
"name": "NCXBIYWT7MV7OAQTCR4QTKBN3X3HDFGSFWTURTCQ22ZZB6NKKJPO7MN4"
}
},
"region3": {
"configured": true,
"connection": {
"cid": 5,
"ip": "::1",
"port": 6500,
"start": "2019-07-24T18:02:48.764685-06:00",
"last_activity": "2019-07-24T18:02:48.764685-06:00",
"uptime": "6s",
"idle": "6s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 0,
"name": "NCVS7Q65WX3FGIL2YQRLI77CE6MQRWO2Y453HYVLNMBMTVLOKMPW7R6K"
}
}
},
"inbound_gateways": {
"region2": [
{
"configured": false,
"connection": {
"cid": 9,
"ip": "::1",
"port": 52029,
"start": "2019-07-24T18:02:48.76677-06:00",
"last_activity": "2019-07-24T18:02:48.767096-06:00",
"uptime": "6s",
"idle": "6s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 0,
"name": "NCXBIYWT7MV7OAQTCR4QTKBN3X3HDFGSFWTURTCQ22ZZB6NKKJPO7MN4"
}
}
],
"region3": [
{
"configured": false,
"connection": {
"cid": 4,
"ip": "::1",
"port": 52025,
"start": "2019-07-24T18:02:48.764577-06:00",
"last_activity": "2019-07-24T18:02:48.764994-06:00",
"uptime": "6s",
"idle": "6s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 0,
"name": "NCVS7Q65WX3FGIL2YQRLI77CE6MQRWO2Y453HYVLNMBMTVLOKMPW7R6K"
}
},
{
"configured": false,
"connection": {
"cid": 8,
"ip": "127.0.0.1",
"port": 52026,
"start": "2019-07-24T18:02:48.766173-06:00",
"last_activity": "2019-07-24T18:02:48.766999-06:00",
"uptime": "6s",
"idle": "6s",
"pending_bytes": 0,
"in_msgs": 0,
"out_msgs": 0,
"in_bytes": 0,
"out_bytes": 0,
"subscriptions": 0,
"name": "NCKCYK5LE3VVGOJQ66F65KA27UFPCLBPX4N4YOPOXO3KHGMW24USPCKN"
}
}
]
}
}
Leaf Node Information (/leafz)
The /leafz endpoint reports detailed information about the leaf node connections.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| subs |
true, 1, false, 0 |
Include internal subscriptions. Default is false. |
As noted above, the leafz endpoint does support the subs argument from the /connz endpoint. For example: https://demo.nats.io:8222/leafz?subs=1
Example
Response
{
"server_id": "NC2FJCRMPBE5RI5OSRN7TKUCWQONCKNXHKJXCJIDVSAZ6727M7MQFVT3",
"now": "2019-08-27T09:07:05.841132-06:00",
"leafnodes": 1,
"leafs": [
{
"account": "$G",
"ip": "127.0.0.1",
"port": 6223,
"rtt": "200µs",
"in_msgs": 0,
"out_msgs": 10000,
"in_bytes": 0,
"out_bytes": 1280000,
"subscriptions": 1,
"subscriptions_list": ["foo"]
}
]
}
Subscription Routing Information (/subsz)
The /subsz endpoint reports detailed information about the current subscriptions and the routing data structure. It is not normally used.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| subs |
true, 1, false, 0 |
Include subscriptions. Default is false. |
| offset |
integer > 0 |
Pagination offset. Default is 0. |
| limit |
integer > 0 |
Number of results to return. Default is 1024. |
| test |
subject |
Test whether a subsciption exists. |
Example
Response
{
"num_subscriptions": 2,
"num_cache": 0,
"num_inserts": 2,
"num_removes": 0,
"num_matches": 0,
"cache_hit_rate": 0,
"max_fanout": 0,
"avg_fanout": 0
}
Account Information (/accountz)
The /accountz endpoint reports information on a server's active accounts. The default behavior is to return a list of all accounts known to the server.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
| Argument |
Value |
Description |
| acc |
account name |
Include metrics for the specified account. Default is empty. When not set, a list of all accounts is included. |
Example
Response
Default behavior:
{
"server_id": "NAB2EEQ3DLS2BHU4K2YMXMPIOOOAOFOAQAC5NQRIEUI4BHZKFBI4ZU4A",
"now": "2021-02-08T17:31:29.551146-05:00",
"system_account": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
"accounts": ["AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5", "$G"]
}
Retrieve specific account:
{
"server_id": "NAB2EEQ3DLS2BHU4K2YMXMPIOOOAOFOAQAC5NQRIEUI4BHZKFBI4ZU4A",
"now": "2021-02-08T17:37:55.80856-05:00",
"system_account": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
"account_detail": {
"account_name": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
"update_time": "2021-02-08T17:31:22.390334-05:00",
"is_system": true,
"expired": false,
"complete": true,
"jetstream_enabled": false,
"leafnode_connections": 0,
"client_connections": 0,
"subscriptions": 42,
"exports": [
{
"subject": "$SYS.DEBUG.SUBSCRIBERS",
"type": "service",
"response_type": "Singleton"
}
],
"jwt": "eyJ0eXAiOiJqd3QiLCJhbGciOiJlZDI1NTE5In0.eyJqdGkiOiJVVlU2VEpXRU8zS0hYWTZVMkgzM0RCVklET1A3U05DTkJPMlM0M1dPNUM2T1RTTDNVSUxBIiwiaWF0IjoxNjAzNDczNzg4LCJpc3MiOiJPQlU1TzVGSjMyNFVEUFJCSVZSR0Y3Q05FT0hHTFBTN0VZUEJUVlFaS1NCSElJWklCNkhENjZKRiIsIm5hbWUiOiJTWVMiLCJzdWIiOiJBQUFYQVVWU0dLN1RDUkhGSVJBUzRTWVhWSjc2RVdETU5YWk02QVJGR1hQN0JBU05ER0xLVTdBNSIsInR5cGUiOiJhY2NvdW50IiwibmF0cyI6eyJsaW1pdHMiOnsic3VicyI6LTEsImNvbm4iOi0xLCJsZWFmIjotMSwiaW1wb3J0cyI6LTEsImV4cG9ydHMiOi0xLCJkYXRhIjotMSwicGF5bG9hZCI6LTEsIndpbGRjYXJkcyI6dHJ1ZX19fQ.CeGo16i5oD0b1uBJ8UdGmLH-l9dL8yNqXHggkAt2T5c88fM7k4G08wLguMAnlvzrdlYvdZvOx_5tHLuDZmGgCg",
"issuer_key": "OBU5O5FJ324UDPRBIVRGF7CNEOHGLPS7EYPBTVQZKSBHIIZIB6HD66JF",
"name_tag": "SYS",
"decoded_jwt": {
"jti": "UVU6TJWEO3KHXY6U2H33DBVIDOP7SNCNBO2S43WO5C6OTSL3UILA",
"iat": 1603473788,
"iss": "OBU5O5FJ324UDPRBIVRGF7CNEOHGLPS7EYPBTVQZKSBHIIZIB6HD66JF",
"name": "SYS",
"sub": "AAAXAUVSGK7TCRHFIRAS4SYXVJ76EWDMNXZM6ARFGXP7BASNDGLKU7A5",
"nats": {
"limits": {
"subs": -1,
"data": -1,
"payload": -1,
"imports": -1,
"exports": -1,
"wildcards": true,
"conn": -1,
"leaf": -1
},
"default_permissions": {
"pub": {},
"sub": {}
},
"type": "account",
"version": 1
}
},
"sublist_stats": {
"num_subscriptions": 42,
"num_cache": 6,
"num_inserts": 42,
"num_removes": 0,
"num_matches": 6,
"cache_hit_rate": 0,
"max_fanout": 1,
"avg_fanout": 0.8333333333333334
}
}
}
Account Statistics (/accstatz)
The /accstatz endpoint reports per-account statistics such as the number of connections, messages/bytes in/out, etc.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| unused |
true, 1, false, 0 |
If true, include accounts that do not have any current connections. Default is false. |
Examples
Response
{
"server_id": "NDJ5M4F5WAIBUA26NJ3QMH532AQPN7QNTJP3Y4SBHSHL4Y7QUAKNJEAF",
"now": "2022-10-19T17:16:20.881296749Z",
"account_statz": [
{
"acc": "default",
"conns": 31,
"leafnodes": 2,
"total_conns": 33,
"num_subscriptions": 45,
"sent": {
"msgs": 1876970,
"bytes": 246705616
},
"received": {
"msgs": 1347454,
"bytes": 219438308
},
"slow_consumers": 29
},
{
"acc": "$G",
"conns": 1,
"leafnodes": 0,
"total_conns": 1,
"num_subscriptions": 3,
"sent": {
"msgs": 0,
"bytes": 0
},
"received": {
"msgs": 107,
"bytes": 1094
},
"slow_consumers": 0
}
]
}
JetStream Information (/jsz)
The /jsz endpoint reports more detailed information on JetStream. For accounts, it uses a paging mechanism that defaults to 1024 connections.
Note: If you're in a clustered environment, it is recommended to retrieve the information from the stream's leader in order to get the most accurate and up-to-date data.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| acc |
account name |
Include metrics for the specified account. Default is unset. |
| accounts |
true, 1, false, 0 |
Include account specific JetStream information. Default is false. |
| streams |
true, 1, false, 0 |
Include streams. When set, implies accounts=true. Default is false. |
| consumers |
true, 1, false, 0 |
Include consumer. When set, implies streams=true. Default is false. |
| config |
true, 1, false, 0 |
When stream or consumer are requested, include their respective configuration. Default is false. |
| leader-only |
true, 1, false, 0 |
Only the leader responds. Default is false. |
| offset |
number > 0 |
Pagination offset. Default is 0. |
| limit |
number > 0 |
Number of results to return. Default is 1024. |
| raft |
true, 1, false, 0 |
Include information details about the Raft group. Default is false. |
Examples
Get basic JetStream information: https://demo.nats.io:8222/jsz
Request accounts and control limit and offset: https://demo.nats.io:8222/jsz?accounts=true\&limit=16\&offset=128.
You can also report detailed consumer information on a per connection basis using consumer=true. For example: https://demo.nats.io:8222/jsz?consumers=true.
Response
{
"server_id": "NCVIDODSZ45C5OD67ZD7EJUIJPQDP6CM74SJX6TJIF2G7NLYS5LCVYHS",
"now": "2021-02-08T19:08:30.555533-05:00",
"config": {
"max_memory": 10485760,
"max_storage": 10485760,
"store_dir": "/var/folders/9h/6g_c9l6n6bb8gp331d_9y0_w0000gn/T/srv_7500251552558",
"unique_tag": "az"
},
"memory": 0,
"storage": 66,
"api": {
"total": 5,
"errors": 0
},
"total_streams": 1,
"total_consumers": 1,
"total_messages": 1,
"total_message_bytes": 33,
"meta_cluster": {
"name": "cluster_name",
"replicas": [
{
"name": "server_5500",
"current": false,
"active": 2932926000
}
]
},
"account_details": [
{
"name": "BCC_TO_HAVE_ONE_EXTRA",
"id": "BCC_TO_HAVE_ONE_EXTRA",
"memory": 0,
"storage": 0,
"api": {
"total": 0,
"errors": 0
}
},
{
"name": "ACC",
"id": "ACC",
"memory": 0,
"storage": 66,
"api": {
"total": 5,
"errors": 0
},
"stream_detail": [
{
"name": "my-stream-replicated",
"cluster": {
"name": "cluster_name",
"replicas": [
{
"name": "server_5500",
"current": false,
"active": 2931517000
}
]
},
"state": {
"messages": 1,
"bytes": 33,
"first_seq": 1,
"first_ts": "2021-02-09T00:08:27.623735Z",
"last_seq": 1,
"last_ts": "2021-02-09T00:08:27.623735Z",
"consumer_count": 1
},
"consumer_detail": [
{
"stream_name": "my-stream-replicated",
"name": "my-consumer-replicated",
"created": "2021-02-09T00:08:27.427631Z",
"delivered": {
"consumer_seq": 0,
"stream_seq": 0
},
"ack_floor": {
"consumer_seq": 0,
"stream_seq": 0
},
"num_ack_pending": 0,
"num_redelivered": 0,
"num_waiting": 0,
"num_pending": 1,
"cluster": {
"name": "cluster_name",
"replicas": [
{
"name": "server_5500",
"current": false,
"active": 2933232000
}
]
}
}
]
}
]
}
]
}
Health (/healthz)
The /healthz endpoint returns OK if the server is able to accept connections.
| Result |
Return Code |
| Success |
200 (OK) |
| Error |
400 (Bad Request) |
Arguments
| Argument |
Values |
Description |
| js-enabled-only |
true, 1 |
Returns an error if JetStream is disabled. |
| js-server-only |
true, 1 |
Skip health check of accounts, streams, and consumers. |
| js-enabled |
true, 1 |
Returns an error if JetStream is disabled. (Deprecated: use js-enabled-only instead). |
Example
Response
Creating Monitoring Applications
NATS monitoring endpoints support JSONP and CORS. You can easily create single page web applications for monitoring. To do this you simply pass the callback query parameter to any endpoint.
For example:
https://demo.nats.io:8222/connz?callback=cb
Here is a JQuery example implementation:
$.getJSON("https://demo.nats.io:8222/connz?callback=?", function (data) {
console.log(data);
});
Monitoring Tools
In addition to writing custom monitoring tools, you can monitor nats-server in Prometheus. The Prometheus NATS Exporter allows you to configure the metrics you want to observe and store in Prometheus, and there are Grafana dashboards available for you to visualize the server metrics.
See the Walkthrough of Monitoring NATS with Prometheus and Grafana for more details.