====== Runbook: Prometheus ======

<WRAP round info>
**Trajanje:** ~15 minuta \\
**Uloga:** DevOps, SRE \\
**Preduvjet:** Prometheus Server, Gateway pokrenut
</WRAP>

Prikupljanje metrika s Data Gatewaya pomocu Prometheusa.

----

===== Tijek rada =====

<mermaid>
flowchart TD
    A[Start] --> B[Metrics aktivirati]
    B --> C[Prometheus Config]
    C --> D[Scrape-Job dodati]
    D --> E[Prometheus reload]
    E --> F[Targets provjeriti]
    F --> G{Up?}
    G -->|Da| H[Gotovo]
    G -->|Ne| I[Firewall/Endpoint provjeriti]

    style H fill:#e8f5e9
    style I fill:#ffebee
</mermaid>

----

===== 1. Metrics u Gatewayu aktivirati =====

**appsettings.json:**

<code json>
{
  "Metrics": {
    "Enabled": true,
    "Endpoint": "/metrics"
  }
}
</code>

**Ili preko NuGet (ako nije ugradeno):**

<code bash>
# prometheus-net.AspNetCore
dotnet add package prometheus-net.AspNetCore
</code>

**Program.cs:**

<code csharp>
// Metrics Middleware
app.UseHttpMetrics();
app.MapMetrics(); // /metrics Endpoint
</code>

----

===== 2. Metrics-Endpoint testirati =====

<code bash>
curl http://localhost:5000/metrics

# Ocekivani izlaz (Prometheus format):
# HELP http_requests_total Total HTTP requests
# TYPE http_requests_total counter
# http_requests_total{method="GET",endpoint="/api/v1/dsn/demo/tables",status="200"} 42
</code>

----

===== 3. Prometheus konfiguracija =====

**/etc/prometheus/prometheus.yml:**

<code yaml>
global:
  scrape_interval: 15s
  evaluation_interval: 15s

scrape_configs:
  # Data Gateway
  - job_name: 'data-gateway'
    static_configs:
      - targets: ['gateway.example.com:5000']
    metrics_path: /metrics
    scheme: http  # ili https

  # Vise instanci
  - job_name: 'data-gateway-cluster'
    static_configs:
      - targets:
          - 'gateway-1.example.com:5000'
          - 'gateway-2.example.com:5000'
          - 'gateway-3.example.com:5000'
</code>

----

===== 4. Prometheus ponovno ucitati =====

<code bash>
# Config-Reload (bez restarta)
curl -X POST http://localhost:9090/-/reload

# Ili Restart
sudo systemctl restart prometheus
</code>

----

===== 5. Targets provjeriti =====

**Web UI:** ''http://prometheus:9090/targets''

Ili preko API:

<code bash>
curl -s http://localhost:9090/api/v1/targets | jq '.data.activeTargets[] | {job: .labels.job, health: .health}'
</code>

**Ocekivani izlaz:**

<code json>
{
  "job": "data-gateway",
  "health": "up"
}
</code>

----

===== 6. Vazni upiti =====

**PromQL primjeri:**

<code>
# Request-Rate (po sekundi)
rate(http_requests_total{job="data-gateway"}[5m])

# Prosjecno vrijeme odgovora
rate(http_request_duration_seconds_sum{job="data-gateway"}[5m])
/
rate(http_request_duration_seconds_count{job="data-gateway"}[5m])

# Error-Rate (5xx)
sum(rate(http_requests_total{job="data-gateway",status=~"5.."}[5m]))
/
sum(rate(http_requests_total{job="data-gateway"}[5m]))

# Memory potrosnja
process_resident_memory_bytes{job="data-gateway"}

# Aktivne konekcije
http_requests_in_progress{job="data-gateway"}
</code>

----

===== 7. Kontrolna lista =====

| # | Provjera | Da/Ne |
|---|-----------|---|
| 1 | Metrics-Endpoint aktiviran | - |
| 2 | /metrics dostupan | - |
| 3 | Prometheus-Config azuriran | - |
| 4 | Prometheus reloadiran | - |
| 5 | Target "up" u Prometheusu | - |
| 6 | Metrike vidljive u Grafani | - |

----

===== Rjesavanje problema =====

| Problem | Uzrok | Rjesenje |
|---------|---------|--------|
| Target "down" | Endpoint nije dostupan | Firewall, URL provjeriti |
| ''connection refused'' | Gateway ne radi | Gateway pokrenuti |
| ''404 Not Found'' | Metrics nije aktiviran | appsettings.json provjeriti |
| Nema metrika | Pogresan put | ''metrics_path'' provjeriti |

----

===== Kubernetes ServiceMonitor =====

Za Prometheus Operator:

<code yaml>
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: data-gateway
  namespace: monitoring
  labels:
    release: prometheus
spec:
  selector:
    matchLabels:
      app: data-gateway
  namespaceSelector:
    matchNames:
      - data-gateway
  endpoints:
    - port: http
      path: /metrics
      interval: 15s
</code>

----

===== Povezani runbookovi =====

  * [[.:grafana-dashboard|Grafana Dashboard]] - Vizualizacija
  * [[.:alerting|Alerting]] - Obavijesti
  * [[..:automatisierung:kubernetes|Kubernetes]] - K8s Deployment

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<< [[.:start|<- Monitoring]] | [[.:grafana-dashboard|-> Grafana Dashboard]] >>

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//Wolfgang van der Stille @ EMSR DATA d.o.o. - Data Gateway Professional//

{{tag>operator runbook prometheus metrics monitoring}}