Prometheus

Prometheus is an open-source monitoring system that's become the standard for cloud-native observability. Butler SOS can expose metrics on a Prometheus-compatible endpoint for scraping.

Why Prometheus?

• Cloud-native - Native support in Kubernetes and modern platforms
• Pull-based - Prometheus scrapes Butler SOS (no push configuration needed)
• PromQL - Powerful query language for dimensional analysis
• Alerting - Built-in alertmanager integration
• Grafana - Excellent integration with Grafana dashboards

How it works

Unlike InfluxDB (where Butler SOS pushes data), Prometheus works by pulling metrics:

1. Butler SOS exposes metrics on an HTTP endpoint
2. Prometheus periodically scrapes that endpoint
3. Metrics are stored in Prometheus' time-series database
4. Grafana (or other tools) query Prometheus for visualization

┌─────────────┐         ┌─────────────┐         ┌─────────────┐
│ Butler SOS  │ ──────► │ Prometheus  │ ──────► │  Grafana    │
│  :9842      │  scrape │             │  query  │             │
└─────────────┘         └─────────────┘         └─────────────┘

Configuration

Butler SOS config

Butler-SOS:
  prometheus:
    enable: true
    host: butler-sos.mycompany.net # IP/FQDN to expose metrics on
    port: 9842 # Port for Prometheus endpoint

Setting	Description
enable	Enable/disable the Prometheus endpoint
host	IP address or hostname to bind to. Use butler-sos.mycompany.net or 0.0.0.0 to listen on all interfaces
port	Port number for the metrics endpoint

Prometheus scrape config

Add Butler SOS as a scrape target in your Prometheus configuration:

scrape_configs:
  - job_name: "butler-sos"
    static_configs:
      - targets: ["butler-sos-host:9842"]
    scrape_interval: 30s

Metrics endpoint

Once enabled, metrics are available at:

http://<butler-sos-host>:9842/metrics

The endpoint returns metrics in Prometheus format:

# HELP butler_sos_engine_cpu_total Engine CPU usage
# TYPE butler_sos_engine_cpu_total gauge
butler_sos_engine_cpu_total{server="sense1.company.com"} 15.2

# HELP butler_sos_engine_memory_committed Engine committed memory
# TYPE butler_sos_engine_memory_committed gauge
butler_sos_engine_memory_committed{server="sense1.company.com"} 8589934592

Prometheus vs InfluxDB

Aspect	Prometheus	InfluxDB
Data collection	Pull (scrape)	Push
Query language	PromQL	InfluxQL / Flux
Best for	Cloud-native, Kubernetes	Traditional deployments
Alerting	Built-in alertmanager	Requires Grafana or Kapacitor
Retention	Limited (usually weeks)	Flexible (days to years)

Both integrate well with Grafana - choose based on your existing infrastructure.