Redirecting...

This page has moved to https://docs.nats.io/nats-server/configuration/monitoring.

Click here if you are not redirected.

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.

The NATS monitoring endpoints support JSONP and CORS, making it easy to create single page monitoring web applications.

Enabling monitoring from the command line

To enable the monitoring server, start the NATS server with the monitoring flag -m and the monitoring port, or turn it on in the configuration file.

-m, --http_port PORT             HTTP PORT for monitoring
-ms,--https_port PORT            Use HTTPS PORT for monitoring

Example:

$ nats-server -m 8222
[4528] 2019/06/01 20:09:58.572939 [INF] Starting nats-server version 2.0.0
[4528] 2019/06/01 20:09:58.573007 [INF] Starting http monitor on port 8222
[4528] 2019/06/01 20:09:58.573071 [INF] Listening for client connections on 0.0.0.0:4222
[4528] 2019/06/01 20:09:58.573090 [INF] nats-server is ready</td>

To test, run nats-server -m 8222, then go to http://demo.nats.io:8222/

Enable monitoring from the configuration file

You can also enable monitoring using the configuration file as follows:

http_port: 8222

For example, to monitor this server locally, the endpoint would be http://demo.nats.io:8222/varz reports various general statistics.

Monitoring endpoints

The following sections describe each supported monitoring endpoint: varz, connz, routez, subsz, and gatewayz. There are not any required arguments, however use of arguments can let you tailor monitoring to your environment and tooling.

General Information

The /varz endpoint returns general information about the server state and configuration.

Endpoint: http://server:port/varz

Result Return Code
Success 200 (OK)
Error 400 (Bad Request)

Arguments

N/A

Example

http://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,
  "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": 0,
  "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"
}

Connection Information

The /connz endpoint reports more detailed information on current and recently closed connections. It uses a paging mechanism which defaults to 1024 connections.

Endpoint: http://server:port/connz

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 Include subscriptions. Default is false.
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 it's id
state open, *closed, any Return connections of partular state. Default is open.

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

Examples

Get up to 1024 connections: http://demo.nats.io:8222/connz

Control limit and offset: http://demo.nats.io:8222/connz?limit=16&offset=128.

Get closed connection information: http://demo.nats.io:8222/connz?state=closed.

You can also report detailed subscription information on a per connection basis using subs=1. For example: http://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": 1,
      "ip": "127.0.0.1",
      "port": 49764,
      "start": "2019-06-24T14:27:25.94611-07:00",
      "last_activity": "2019-06-24T14:27:25.954046-07:00",
      "rtt": "275µs",
      "uptime": "50s",
      "idle": "50s",
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 1,
      "name": "NATS Sample Subscriber",
      "lang": "go",
      "version": "1.8.1",
      "subscriptions_list": [
        "hello.world"
      ]
    },
    {
      "cid": 2,
      "ip": "127.0.0.1",
      "port": 49767,
      "start": "2019-06-24T14:27:43.403923-07:00",
      "last_activity": "2019-06-24T14:27:43.406568-07:00",
      "rtt": "96µs",
      "uptime": "33s",
      "idle": "33s",
      "pending_bytes": 0,
      "in_msgs": 0,
      "out_msgs": 0,
      "in_bytes": 0,
      "out_bytes": 0,
      "subscriptions": 1,
      "name": "NATS Sample Subscriber",
      "lang": "go",
      "version": "1.8.1",
      "subscriptions_list": [
        "foo.bar"
      ]
    }
  ]
}

Route Information

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.

Endpoint: http://server:port/routez

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 routez endpoint does support the subs argument from the /connz endpoint. For example: http://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

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.

Endpoint: http://server:port/gatewayz

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 Nodes Information

The /leafz endpoint reports detailed information about the leaf node connections.

Endpoint: http://server:port/leafz

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: http://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

The /subz endpoint reports detailed information about the current subscriptions and the routing data structure. It is not normally used.

Endpoint: http://server:port/subz

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
}

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:

http://demo.nats.io:8222/connz?callback=cb

Here is a JQuery example implementation:

$.getJSON('http://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. There's a sample Grafana dashboard that you can use to visualize the server metrics.

results matching ""

    No results matching ""