====== Runbook: Alerting ======

<WRAP round info>
**Durata:** ~15 minuti \\
**Ruolo:** DevOps, SRE \\
**Prerequisito:** Prometheus, Alertmanager
</WRAP>

Notifiche automatiche per problemi Gateway.

----

===== Workflow =====

<mermaid>
flowchart TD
    A[Start] --> B[Definire regole Alert]
    B --> C[Configurare Alertmanager]
    C --> D[Configurare Receiver]
    D --> E[Attivare Test-Alert]
    E --> F{Notifica ricevuta?}
    F -->|Si| G[Finito]
    F -->|No| H[Controllare Config]

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

----

===== 1. Regole Alert (Prometheus) =====

**/etc/prometheus/rules/gateway-alerts.yml:**

<code yaml>
groups:
  - name: data-gateway
    interval: 30s
    rules:
      # Gateway non raggiungibile
      - alert: GatewayDown
        expr: up{job="data-gateway"} == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "Data Gateway non raggiungibile"
          description: "{{ $labels.instance }} non raggiungibile da 1 minuto."

      # Alto Error-Rate
      - alert: GatewayHighErrorRate
        expr: |
          sum(rate(http_requests_total{job="data-gateway",status=~"5.."}[5m]))
          /
          sum(rate(http_requests_total{job="data-gateway"}[5m]))
          > 0.05
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Alto tasso di errori nel Gateway"
          description: "Error-Rate e {{ $value | humanizePercentage }} (> 5%)."

      # Tempi di risposta lenti
      - alert: GatewaySlowResponses
        expr: |
          histogram_quantile(0.95,
            sum(rate(http_request_duration_seconds_bucket{job="data-gateway"}[5m])) by (le)
          ) > 2
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Gateway risponde lentamente"
          description: "P95 Response-Zeit e {{ $value | humanizeDuration }}."

      # Alto consumo memoria
      - alert: GatewayHighMemory
        expr: |
          process_resident_memory_bytes{job="data-gateway"}
          / 1024 / 1024 > 450
        for: 10m
        labels:
          severity: warning
        annotations:
          summary: "Gateway consuma molta memoria"
          description: "Utilizzo memoria e {{ $value | humanize }}MB."

      # Certificato in scadenza
      - alert: GatewayCertExpiringSoon
        expr: |
          (probe_ssl_earliest_cert_expiry{job="gateway-tls"} - time())
          / 86400 < 14
        for: 1h
        labels:
          severity: warning
        annotations:
          summary: "Certificato TLS Gateway in scadenza"
          description: "Certificato scade tra {{ $value | humanize }} giorni."
</code>

----

===== 2. Aggiornare Config Prometheus =====

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

<code yaml>
rule_files:
  - "rules/*.yml"

alerting:
  alertmanagers:
    - static_configs:
        - targets:
            - alertmanager:9093
</code>

<code bash>
# Ricaricare Prometheus
curl -X POST http://localhost:9090/-/reload
</code>

----

===== 3. Configurazione Alertmanager =====

**/etc/alertmanager/alertmanager.yml:**

<code yaml>
global:
  resolve_timeout: 5m
  smtp_smarthost: 'smtp.example.com:587'
  smtp_from: 'alertmanager@example.com'
  smtp_auth_username: 'alertmanager@example.com'
  smtp_auth_password: 'secret'

route:
  group_by: ['alertname', 'severity']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 4h
  receiver: 'default'
  routes:
    # Alert critici subito
    - match:
        severity: critical
      receiver: 'critical'
      group_wait: 10s
      repeat_interval: 1h

receivers:
  - name: 'default'
    email_configs:
      - to: 'ops@example.com'
        send_resolved: true

  - name: 'critical'
    email_configs:
      - to: 'oncall@example.com'
        send_resolved: true
    slack_configs:
      - api_url: 'https://hooks.slack.com/services/XXX/YYY/ZZZ'
        channel: '#alerts-critical'
        send_resolved: true
        title: '{{ .Status | toUpper }}: {{ .CommonAnnotations.summary }}'
        text: '{{ .CommonAnnotations.description }}'

inhibit_rules:
  - source_match:
      severity: 'critical'
    target_match:
      severity: 'warning'
    equal: ['alertname', 'instance']
</code>

----

===== 4. Integrazione Slack =====

<code yaml>
# Solo parte Slack
receivers:
  - name: 'slack-alerts'
    slack_configs:
      - api_url: 'https://hooks.slack.com/services/XXX/YYY/ZZZ'
        channel: '#gateway-alerts'
        send_resolved: true
        title: '{{ if eq .Status "firing" }}ALERT{{ else }}OK{{ end }} {{ .CommonAnnotations.summary }}'
        text: |
          *Alert:* {{ .CommonLabels.alertname }}
          *Severity:* {{ .CommonLabels.severity }}
          *Description:* {{ .CommonAnnotations.description }}
          *Instance:* {{ .CommonLabels.instance }}
</code>

----

===== 5. Microsoft Teams =====

<code yaml>
# Via Prometheus MS Teams Webhook
receivers:
  - name: 'teams-alerts'
    webhook_configs:
      - url: 'http://prometheus-msteams:2000/gateway'
        send_resolved: true
</code>

----

===== 6. Test-Alert =====

<code bash>
# Controllare regole Alert
curl http://localhost:9090/api/v1/rules | jq '.data.groups[].rules[] | {alert: .name, state: .state}'

# Alert attivi
curl http://localhost:9090/api/v1/alerts | jq '.data.alerts[]'

# Stato Alertmanager
curl http://localhost:9093/api/v2/status | jq

# Inviare Test-Alert
curl -X POST http://localhost:9093/api/v2/alerts \
  -H "Content-Type: application/json" \
  -d '[{
    "labels": {"alertname": "TestAlert", "severity": "warning"},
    "annotations": {"summary": "Test-Alert", "description": "Questo e un test."}
  }]'
</code>

----

===== 7. Checklist =====

| # | Punto di verifica | v |
|---|-----------|---|
| 1 | Regole Alert create | ☐ |
| 2 | Prometheus config aggiornata | ☐ |
| 3 | Alertmanager configurato | ☐ |
| 4 | Receiver testato (E-Mail/Slack) | ☐ |
| 5 | Test-Alert ricevuto | ☐ |

----

===== Troubleshooting =====

| Problema | Causa | Soluzione |
|---------|---------|--------|
| ''No alerts'' | Sintassi regola errata | ''promtool check rules rules.yml'' |
| ''Alert not firing'' | Condizione non soddisfatta | Testare query manualmente |
| ''No notification'' | Receiver errato | Controllare log Alertmanager |
| ''Duplicate alerts'' | Raggruppamento errato | Modificare ''group_by'' |

----

===== Soglie Raccomandate =====

| Alert | Soglia | Durata |
|-------|-------------|-------|
| GatewayDown | up == 0 | 1m |
| HighErrorRate | > 5% | 5m |
| SlowResponses | p95 > 2s | 5m |
| HighMemory | > 450MB | 10m |
| CertExpiring | < 14 giorni | 1h |

----

===== Runbook Correlati =====

  * [[.:prometheus|Prometheus]] - Raccogliere metriche
  * [[.:grafana-dashboard|Grafana]] - Visualizzazione
  * [[..:sicherheit:tls-einrichten|Configurare TLS]] - Alerting certificati

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

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

{{tag>operator runbook alerting prometheus alertmanager}}