NATS Monitoring, Simplified.
NATS surveyor polls the NATS server for Statz messages to generate data for
Prometheus. This allows a single exporter to connect to any NATS server and
get an entire picture of a NATS deployment without requiring extra monitoring
components or sidecars. Surveyor has been used extensively by Synadia.
System accounts must be enabled to use surveyor.
nats-surveyor [flags]
Flags:
-s, --servers string NATS Cluster url(s) (default "nats://127.0.0.1:4222")
-c, --count int Expected number of servers (-1 for undefined). (default 1)
--timeout duration Polling timeout (default 3s)
--server-discovery-timeout duration Maximum wait time between responses from servers during server discovery.
Use in conjunction with -count=-1. (default 500ms)
--creds string Credentials File
--nkey string Nkey Seed File
--jwt string User JWT. Use in conjunction with --seed
--seed string Private key (nkey seed). Use in conjunction with --jwt
--user string NATS user name or token
--password string NATS user password
--tlscert string Client certificate file for NATS connections.
--tlskey string Client private key for NATS connections.
--tlscacert string Client certificate CA on NATS connections.
--tlsfirst Whether to use TLS First connections.
-p, --port int Port to listen on. (default 7777)
-a, --addr string Network host to listen on. (default "0.0.0.0")
--http-tlscert string Server certificate file (Enables HTTPS).
--http-tlskey string Private key for server certificate (used with HTTPS).
--http-tlscacert string Client certificate CA for verification (used with HTTPS).
--http-user string Enable basic auth and set user name for HTTP scrapes.
--http-pass string Set the password for HTTP scrapes. NATS bcrypt supported.
--prefix string Replace the default prefix for all the metrics.
--observe string Listen for observation statistics based on config files in a directory.
--jetstream string Listen for JetStream Advisories based on config files in a directory.
--accounts Export per account metrics
--gatewayz Export gateway metrics
--jsz string Export jsz metrics optionally, one of: all|streams|consumers
--jsz-leaders-only bool Fetch jsz data from stream and consumer leaders only
--jsz-filter stringArray Export jsz consumer metrics that match selected filters
--sys-req-prefix string Subject prefix for system requests ($SYS.REQ) (default "$SYS.REQ")
--log-level string Log level, one of: trace|debug|info|warn|error|fatal|panic (default "info")
--config string config file (default is ./nats-surveyor.yaml)
-h, --help help for nats-surveyor
-v, --version version for nats-surveyor
At this time, NATS 2.0 System credentials are required for meaningful usage. Those can be provided in 2 ways:
- using
--credsoption to supply chained credentials file (containing JWT and NKey seed):
./nats-surveyor --creds ./test/SYS.creds
2019/10/14 21:35:40 Connected to NATS Deployment: 127.0.0.1:4222
2019/10/14 21:35:40 No certificate file specified; using http.
2019/10/14 21:35:40 Prometheus exporter listening at http://0.0.0.0:7777/metrics- using
--jwtand--seedoptions to provide user JWT and NKey seed directly:
./nats-surveyor --jwt $NATS_USER_JWT --seed $NATS_NKEY_SEED
2019/10/14 21:35:40 Connected to NATS Deployment: 127.0.0.1:4222
2019/10/14 21:35:40 No certificate file specified; using http.
2019/10/14 21:35:40 Prometheus exporter listening at http://0.0.0.0:7777/metricsSurveyor uses Viper to read configs, so it will support all file types that Viper supports (JSON, TOML, YAML, HCL, envfile, and Java properties)
To use a config file pass the --config flag. The defaults are /etc/nats-surveyor/nats-surveyor[.ext] and ./nats-surveyor[.ext] with one of the supported extensions.
The config is simple, just set each flag in the config file. Example nats-surveyor.yaml:
servers: nats://127.0.0.1:4222
accounts: true
log-level: debugEnvironment variables are also taken into account. Any environment variable that is prefixed with NATS_SURVEYOR_ will be read.
Each flag has a matching environment variable, flag names should be converted to uppercase and dashes replaced with underscores. Example:
NATS_SURVEYOR_SERVERS=nats://127.0.0.1:4222
NATS_SURVEYOR_ACCOUNTS=true
NATS_SURVEYOR_LOG_LEVEL=debug
Scrape output is the in form of nats_core_NNNN_metric, where NNN is server, route, or gateway.
To aid filtering, each metric has labels. These include server_cluster, server_name, and server_id.
Routes have the additional label server_route_name and gateways have the additional label server_gateway_name.
The info metrics has a nats_server_version label with the current version.
Additionally, there is a nats_up metric that will normally return 1, but will return 0
and no additional NATS metrics when there is no connectivity to the NATS system. This
allows users to differentiate between a problem with the exporter itself connectivity with
the NATS system.
Since v0.9.1, nats-surveyor supports collecting stream and consumer metrics. By default, surveyor will collect all the metrics from all the replicas from streams and consumers which depending of the size of your deployment, can result in high cardinality issues in the Prometheus setup. To narrow down the list of metrics to be exported there are a few options.
-
Using
--jsz=streamsto make sure that only the streams metrics is collected (if consumer metrics are not needed). -
Using
--jsz-leaders-onlyto skip data from the stream and consumer replicas. -
Using
--jsz-filterto decrease number of consumer metrics:The following list of metrics for consumers is available to be used as filters:
consumer_delivered_consumer_seq consumer_delivered_stream_seq consumer_ack_floor_consumer_seq consumer_ack_floor_stream_seq consumer_num_ack_pending consumer_num_pending consumer_num_redelivered consumer_num_waiting
For example, the following will make surveyor only collect the metrics from the leaders
and picking up num_pending, num_ack_pending and num_waiting from the consumers.
nats-surveyor --jsz=all \
--jsz-leaders-only \
--jsz-filter=consumer_num_pending,consumer_num_ack_pending,consumer_num_waiting
An easy way to start the NATS Surveyor stack (Grafana, Prometheus, and NATS Surveyor) is through docker-compose.
Follow these links for installation instructions:
The following environment variables MUST be set, either in your environment or
through the .env file that is automatically read by
docker-compose. There is a survey.sh script that will set them for you as
a convenience.
| Environment Variable | Example | Description |
|---|---|---|
| NATS_SURVEYOR_SERVERS | nats://hostname:4222 | The URLs of any deployed NATS server(s) |
| NATS_SURVEYOR_CREDS | ./SYS.creds | NATS 2.0 System Account credentials |
| NATS_SURVEYOR_SERVER_COUNT | 9 | Number of expected NATS servers |
| PROMETHEUS_STORAGE | ./storage/prometheus | Path to store prometheus data locally |
| SURVEYOR_DOCKER_TAG | latest | Surveyor docker tag to pull |
| PROMETHEUS_DOCKER_TAG | latest | Prometheus docker tag to pull |
| GRAFANA_DOCKER_TAG | latest | Grafana docker tag to pull |
Note: For referencing files and paths, docker always expects volume mounts
to be either a fully qualified directory, or a relative directory beginning
with with ./.
You only need to connect to a single NATS server to monitor your entire NATS
deployment. In configuring NATS_SURVEYOR_SERVERS, only one server is required,
but it's recommended you provide a list for backup servers to connect to, e.g.
nats://host1:4222,nats://host2:5222. Valid urls are formatted as hostname
(defaulting to port 4222), hostname:port, or nats://hostname:port.
You can start the Surveyor stack two ways. The first is through docker
compose. Ensure the environment varibles are set, that you are working
from the /docker-compose directory and run docker-compose up.
$ docker-compose up
Recreating nats-surveyor ... done
Recreating prometheus ... done
Recreating grafana ... done
Attaching to nats-surveyor, prometheus, grafana
...Alternatively, you can pass variables into the survey.sh script in the
docker-compose directory.
$ ./survey.sh
usage: survey.sh <url> <server count> <system credentials>e.g.
./survey.sh nats://mydeployment:4222 24 /privatekeys/SYS.creds
If things aren't working, look in the output for any lines that contain
exited with code 1 and address the problem. They are usually docker
volume mount problems or connectivity problems.
Next, with your browser, navigate to http://127.0.0.1:3000, or if you are
running the Surveyor stack remotely, the hostname of the host running the
NATS surveyor stack, e.g. http://yourremotehost:3000.
The first time you connect, you'll need to login:
- User: admin
- Password: admin
After logging in, navigate to "Manage dashboards" and you'll see a dashboard available named NATS Surveyor, where you'll be able to monitor your entire NATS deployment.
To stop the surveyor stack, but keep the containers run: docker-compose stop
To restart the surveyor stack after being stopped, run: docker-compose up
To cleanup your installation, run: docker-compose down
For platforms that support systemd, surveyor.service
is provided as a service definition template. Modify and save this file as
/etc/systemd/system/surveyor.service.
systemctl start surveyor will launch the service.
The logs should normally contain enough information about the cause of problems or errors.
If you encounter a Prometheus error of:
panic: Unable to create mmap-ed active query log, set the UID of the
container to match the UID of your user in the
docker-compose file.
e.g:
prometheus:
image: prom/prometheus:${PROMETHEUS_DOCKER_TAG}
user: "1000:1000"If the above doesn't work, using root will work but may pose a
security thread to the node it is running on.
prometheus:
image: prom/prometheus:${PROMETHEUS_DOCKER_TAG}
user: rootMore information can be found here.
Services can be observed by creating JSON files in the observations directory.
The file extension must be .json.
Only one authentication method needs to be provided.
Example file format:
{
"name": "my service",
"topic": "email.subscribe.>",
"jwt": "jwt portion of creds, must include seed also",
"seed": "seed portion of creds, must include jwt also",
"credential": "/path/to/file.creds",
"nkey": "nkey seed",
"token": "token",
"username": "username, must include password also",
"password": "password, must include user also",
"tls_ca": "/path/to/ca.pem, defaults to surveyor's ca if one exists",
"tls_cert": "/path/to/cert.pem, defaults to surveyor's cert if one exists",
"tls_key": "/path/to/key.pem, defaults to surveyor's key if one exists"
}Files are watched and updated using fsnotify
JetStream can be monitored on a per-account basis by creating JSON files in the jetstream directory.
The file extension must be .json.
Only one authentication method needs to be provided.
e sure that you give access to the $JS.EVENT.> subject to your user.
Example file format:
{
"name": "my account",
"jwt": "jwt portion of creds, must include seed also",
"seed": "seed portion of creds, must include jwt also",
"credential": "/path/to/file.creds",
"nkey": "nkey seed",
"token": "token",
"username": "username, must include password also",
"password": "password, must include user also",
"tls_ca": "/path/to/ca.pem, defaults to surveyor's ca if one exists",
"tls_cert": "/path/to/cert.pem, defaults to surveyor's cert if one exists",
"tls_key": "/path/to/key.pem, defaults to surveyor's key if one exists"
}Files are watched and updated using fsnotify
- Windows builds
- Other events (connections, disconnects, etc)
- Best Guess Server Count
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