Alerting

Observability workspaces include a Prometheus-compatible ruler (alert and recording rules) and Alertmanager for routing notifications. Manage configuration from the console, with mimirtool, or via compatible APIs against the workspace gateway.

Overview

Component	Role
Alert rules	PromQL conditions that fire alerts
Recording rules	Pre-computed PromQL results for faster queries
Alertmanager	Groups, silences, and routes alerts to receivers

Metrics alerting runs in the workspace metrics backend. Log-based alerting is not covered on this page.

Create alert rules

groups:
  - name: infrastructure
    interval: 30s
    rules:
      - alert: HighCPUUsage
        expr: 100 - (avg(rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100) > 80
        for: 5m
        labels:
          severity: warning
          team: platform
        annotations:
          summary: "High CPU usage detected"
          description: "CPU usage is {{ $value }}% on {{ $labels.instance }}"

Field	Meaning
`expr`	PromQL that must be true for the alert to fire
`for`	Duration the condition must hold before firing
`labels`	Attached to the alert for routing
`annotations`	Human-readable summary and description

Recording rules

groups:
  - name: recording_rules
    interval: 30s
    rules:
      - record: instance:node_cpu:rate5m
        expr: rate(node_cpu_seconds_total[5m])
      - record: instance:node_memory:usage_percent
        expr: (1 - (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes)) * 100

Console

Open the workspace.
Use Rules to create or edit rule groups.
Use Alerts to review firing/pending alerts and manage Alertmanager configuration and silences.

The principal needs ruler and Alertmanager data-plane permissions on the workspace.

Managing rules with mimirtool

Point mimirtool at the workspace metrics gateway and use the workspace ID as the tenant ID.

Authenticate with a Thalassa Cloud bearer token — for example a personal access token or an access token from a service account. For CI pipelines that use workload identity, exchange an ID token with tcloud oidc token-exchange (see OIDC).

export MIMIR_ADDRESS=https://prometheus.<region>.thalassa.cloud/workspace/obsw-<id>
export MIMIR_TENANT_ID=obsw-<id>
export THALASSA_BEARER_TOKEN="<your-access-token>"

mimirtool rules load rules.yaml \
  --address "$MIMIR_ADDRESS" \
  --id "$MIMIR_TENANT_ID" \
  --token "$THALASSA_BEARER_TOKEN"

mimirtool rules list \
  --address "$MIMIR_ADDRESS" \
  --id "$MIMIR_TENANT_ID" \
  --token "$THALASSA_BEARER_TOKEN"

mimirtool alertmanager load alertmanager.yaml \
  --address "$MIMIR_ADDRESS" \
  --id "$MIMIR_TENANT_ID" \
  --token "$THALASSA_BEARER_TOKEN"

Install mimirtool from the Grafana Mimir releases. Flag names can vary by mimirtool version (--tenant-id vs --id); use the flags for your installed version.

Gateway APIs

Ruler and Alertmanager HTTP APIs are available under the workspace metrics base URL (same host/path prefix as remote write). Authenticate with Authorization: Bearer <token>.

Examples (adjust paths to match the workspace alerting URLs shown in the console):

# List rule groups
curl -H "Authorization: Bearer $TOKEN" \
  "https://prometheus.<region>.thalassa.cloud/workspace/obsw-<id>/api/v1/rules"

# Alertmanager status / alerts
curl -H "Authorization: Bearer $TOKEN" \
  "https://prometheus.<region>.thalassa.cloud/workspace/obsw-<id>/alertmanager/api/v2/alerts"

Prefer the URLs from the workspace overview (alertingUrl and related paths) when integrating automation.

Alert routing

route:
  group_by: ["alertname", "cluster"]
  group_wait: 10s
  group_interval: 10s
  repeat_interval: 12h
  receiver: "default"
  routes:
    - matchers:
        - severity="critical"
      receiver: "pager"
    - matchers:
        - severity="warning"
      receiver: "slack-alerts"

Configure receivers for SMTP, webhooks, Slack, Microsoft Teams, or other Alertmanager-supported integrations.