NRPE exporter

The NRPE exporter exposes metrics on commands sent to a running NRPE daemon.

Building and running

Local Build

go build nrpe_exporter.go
./nrpe_exporter

Visiting http://localhost:9275/export?command=check_load&target=127.0.0.1:5666 will return metrics for the command 'check_load' against a locally running NRPE server.

Building with Docker

docker build -t nrpe_exporter .
docker run -d -p 9275:9275 --name nrpe_exporter

Configuration

The nrpe_exporter requires little to no configuration.

The few options available such as logging level and the port to run on are configured via command line flags.

Run ./nrpe_exporter -h to view all available flags.

Prometheus Configuration

Example config:

global:
  scrape_interval: 10s
scrape_configs:
  - job_name: nrpe_check_load
    metrics_path: /export
    params:
      command: [check_load] # Run the check_load command.
      ssl: [true] # if using ssl
    static_configs:
      - targets: # Targets to run the specified command against.
        - '127.0.0.1:5666'
        - 'example.com:5666'
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 127.0.0.1:9275 # Nrpe exporter.

Result Codes in command_status:

    StatusOK       = 0
    StatusWarning  = 1
    StatusCritical = 2
    StatusUnknown  = 3

Sample Alert Rule:

groups:
- name: NRPE Host Load Status
  rules:
  - alert: HighLoad
    expr: avg_over_time(command_status{job="nrpe_check_load"}[5m]) > 0
    for: 5m
    annotations:
      summary: "Load is high {{ $labels.instance }}"
      description: "{{ $labels.instance }} for job {{ $labels.job }} has sustained high load."

SSL support

Add URL query parameter ssl=true to enable SSL for the NRPE connection, e.g.

    params:
      command: [check_load]
      ssl: [true]

NRPE requires the ADH ciphersuite which is not built by default in modern version of openssl. If the following command returns nothing then you will not be able to use it:

openssl ciphers -s -v ALL | grep ADH   # remove -s on older versions of openssl

The solution is to build a statically-linked nrpe_exporter binary on an older server - Ubuntu 16.04 works.

go build -a -ldflags '-extldflags "-static -ldl"'

A trivial Makefile is provided, which will perform this task in Docker.