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Configuration

UAR is designed so that it very much works "out of the box" and with zero configuration. However, it's entirely possible that people might want to tweak things, so there are some configuration options provided.

Configuration options

ALERTMANAGER_HOST Environment Variable

This is the browser URL to get to alertmanager. If you set this, alert links will be clickable. eg: https://am.webapps.example.com.

WEBHOOK_TOKEN Environment Variable

Optional shared secret for POST /alerts. When set, Alertmanager (or any client) must send Authorization: Bearer <token>. When unset, the webhook stays open — keep UAR on a trusted network in that case.

The UI and /api/* read endpoints stay unauthenticated on purpose; place them behind your network perimeter (VPN, reverse proxy allowlist, etc.).

CORS_ORIGIN Environment Variable

Controls the Access-Control-Allow-Origin header on /api/settings and /api/alert_list.

  • Unset or empty (default): no CORS header (same-origin UI works as usual).
  • A concrete origin (eg. https://noc.example.com): that origin is allowed.
  • *: restore the previous open CORS behaviour if you need it.

SEV_LABELS_... Environment Variables

The default severity labels are;

  • SEV_LABELS_1: crit,critical
  • SEV_LABELS_2: severe
  • SEV_LABELS_3: warning
  • SEV_LABELS_4: important
  • SEV_LABELS_5: info,information

DRAW_LABELS Environment Variable

When set to any non-empty value, UAR will show Prometheus labels on each alert box by default. You can also toggle label display from the logo menu in the UI; that preference is stored in the browser.

IGNORED_LABELS Environment Variable

A comma-separated list of label names that should not be drawn when labels are shown. The default is alertname,instance,job,severity.

Built-in limits

Webhook requests are capped to protect memory:

  • Request body: 1 MiB maximum (larger payloads return 413).
  • Stored alerts: 1000 maximum distinct alerts. Updates and resolves for existing alerts still work at capacity; inserting a new alert when full returns 503 so Alertmanager can retry.