Implement Grafana advanced alerting with webhooks and notification channels

Update system packages

Start by updating your package manager to ensure you have the latest security patches.

sudo apt update && sudo apt upgrade -y

sudo dnf update -y

Install Grafana if not already present

Install Grafana from the official repository if you don't have it running yet.

wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add -
echo "deb https://packages.grafana.com/oss/deb stable main" | sudo tee /etc/apt/sources.list.d/grafana.list
sudo apt update
sudo apt install -y grafana

sudo dnf install -y https://dl.grafana.com/oss/release/grafana-10.2.3-1.x86_64.rpm

Configure Grafana for unified alerting

Enable unified alerting in the main configuration file and set retention policies.

[unified_alerting]
enabled = true

[alerting]
enabled = false

Alert rule evaluation interval
[unified_alerting.evaluation]
max_attempts = 3
min_interval = 10s

Data retention for alert instances
[unified_alerting.state_history]
enabled = true
max_age = 168h

Screenshot settings for alert notifications
[unified_alerting.screenshots]
capture = true
max_concurrent_screenshots = 5

Start and enable Grafana

Start the Grafana service and enable it to run on boot.

sudo systemctl start grafana-server
sudo systemctl enable grafana-server
sudo systemctl status grafana-server

Configure Prometheus data source

Add a Prometheus data source through the Grafana web interface at http://your-server:3000. Navigate to Configuration > Data Sources > Add data source > Prometheus.

Name: Prometheus
URL: http://localhost:9090
Access: Server (default)
Scrape interval: 15s
Query timeout: 60s
HTTP Method: POST

Click "Save & Test" to verify the connection works.

Create contact points for notifications

Navigate to Alerting > Contact points > Add contact point. Create separate contact points for each notification method.

Slack Contact Point:

Name: slack-alerts
Integration: Slack
Webhook URL: https://hooks.slack.com/services/YOUR/SLACK/WEBHOOK
Channel: #alerts
Username: Grafana
Title: {{ template "slack.default.title" . }}
Text: {{ template "slack.default.text" . }}

Microsoft Teams Contact Point:

Name: teams-alerts
Integration: Microsoft Teams
Webhook URL: https://your-tenant.webhook.office.com/webhookb2/YOUR-WEBHOOK-URL
Title: {{ template "teams.default.title" . }}
Summary: {{ template "teams.default.summary" . }}

Email Contact Point:

Name: email-alerts
Integration: Email
Addresses: ops-team@example.com, alerts@example.com
Subject: [GRAFANA] {{ .GroupLabels.alertname }}
Message: {{ range .Alerts }}{{ .Annotations.summary }}{{ end }}

Configure SMTP for email notifications

Update Grafana's SMTP settings to enable email notifications.

[smtp]
enabled = true
host = smtp.gmail.com:587
user = your-email@gmail.com
password = your-app-password
cert_file =
key_file =
skip_verify = false
from_address = grafana@example.com
from_name = Grafana Alerts
ehlo_identity = example.com
startTLS_policy = MandatoryStartTLS

Restart Grafana after updating SMTP settings:

sudo systemctl restart grafana-server

Create custom webhook endpoint

Set up a webhook contact point for external integrations like PagerDuty or custom applications.

Name: custom-webhook
Integration: Webhook
URL: https://api.example.com/v1/alerts
HTTP Method: POST
Authorization Header: Bearer YOUR-API-TOKEN
Content-Type: application/json
Body:
{
  "alert_name": "{{ .GroupLabels.alertname }}",
  "status": "{{ .Status }}",
  "severity": "{{ .GroupLabels.severity }}",
  "summary": "{{ range .Alerts }}{{ .Annotations.summary }}{{ end }}",
  "timestamp": "{{ .Alerts.Firing | len }}",
  "firing_alerts": {{ .Alerts.Firing | len }},
  "resolved_alerts": {{ .Alerts.Resolved | len }}
}

Create notification policies

Navigate to Alerting > Notification policies. Configure routing based on alert labels and severity.

# Root policy (catches all alerts)
Default contact point: email-alerts
Group by: alertname, instance
Group wait: 10s
Group interval: 5m
Repeat interval: 12h

High severity alerts
Matchers:
severity = critical
Contact point: slack-alerts, teams-alerts, custom-webhook
Group wait: 0s
Repeat interval: 5m
Override grouping: true

Warning alerts
Matchers:
severity = warning
Contact point: slack-alerts
Group interval: 10m
Repeat interval: 4h

Create advanced alert rules

Navigate to Alerting > Alert rules > New rule. Create comprehensive alert rules with multiple conditions.

CPU Usage Alert Rule:

Rule name: High CPU Usage
Folder: Infrastructure
Group: System Metrics

Query A - Current CPU usage
Query: 100 - (avg(rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100)
Alias: cpu_usage

Query B - CPU usage trend (15min average)
Query: avg_over_time((100 - (avg(rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100))[15m:])
Alias: cpu_trend

Condition
Expression: $cpu_usage > 80 AND $cpu_trend > 70
Evaluation: Last value, IS ABOVE, 0

Evaluation behavior
Evaluate every: 1m
For: 5m

Labels
severity: warning
team: infrastructure
service: system

Annotations
summary: High CPU usage detected on {{ $labels.instance }}
description: CPU usage is {{ $values.cpu_usage | humanize }}% (15min avg: {{ $values.cpu_trend | humanize }}%)

Create memory usage alert with templating

Create a more complex alert rule for memory usage with custom templating.

Rule name: High Memory Usage
Folder: Infrastructure
Group: System Metrics

Query A - Available memory percentage
Query: (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes) * 100
Alias: memory_available

Query B - Memory usage percentage
Query: 100 - ((node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes) * 100)
Alias: memory_usage

Condition
Expression: $memory_available < 15
Evaluation: Last value, IS BELOW, 15

Evaluation behavior
Evaluate every: 30s
For: 2m

Labels
severity: critical
team: infrastructure
service: system
runbook_url: https://wiki.example.com/runbooks/memory-alerts

Annotations with advanced templating
summary: Memory usage critical on {{ $labels.instance }}
description: |
  Memory usage is {{ $values.memory_usage | printf "%.1f" }}% ({{ printf "%.1f" (100 - $values.memory_available) }}% used)
  Available memory: {{ $values.memory_available | printf "%.1f" }}%
  Instance: {{ $labels.instance }}
  Job: {{ $labels.job }}
  
  Runbook: {{ $labels.runbook_url }}

Create application-specific alert rules

Set up alerts for application metrics like HTTP response times and error rates.

Rule name: High HTTP Error Rate
Folder: Applications
Group: Web Services

Query A - Error rate calculation
Query: rate(http_requests_total{status=~"5.."}[5m]) / rate(http_requests_total[5m]) * 100
Alias: error_rate

Query B - Request volume
Query: rate(http_requests_total[5m])
Alias: request_rate

Condition
Expression: $error_rate > 5 AND $request_rate > 1
Evaluation: Last value, IS ABOVE, 0

Evaluation behavior
Evaluate every: 30s
For: 3m

Labels
severity: critical
team: backend
service: {{ $labels.service }}
environment: {{ $labels.environment }}

Annotations
summary: High error rate for {{ $labels.service }}
description: |
  Error rate: {{ $values.error_rate | printf "%.2f" }}%
  Request rate: {{ $values.request_rate | printf "%.1f" }} req/s
  Service: {{ $labels.service }}
  Environment: {{ $labels.environment }}
  Instance: {{ $labels.instance }}

Configure alert rule groups and folders

Organize alerts into logical groups for better management. Navigate to Alerting > Alert rules and create folders.

Folders:
├── Infrastructure
│   ├── System Metrics (CPU, Memory, Disk)
│   ├── Network (Connectivity, Bandwidth)
│   └── Database (MySQL, PostgreSQL, Redis)
├── Applications
│   ├── Web Services (HTTP errors, latency)
│   ├── Background Jobs (Queue length, failures)
│   └── API Endpoints (Rate limits, timeouts)
└── Business Metrics
    ├── User Activity (Logins, signups)
    ├── Revenue (Transactions, conversions)
    └── Performance (Page load, API response)

Create silences and maintenance windows

Set up alert silences for planned maintenance. Navigate to Alerting > Silences > New silence.

Matchers:
service = "web-frontend"
environment = "production"
Start: 2024-01-15 02:00 UTC
End: 2024-01-15 04:00 UTC
Timezone: UTC

Created by: ops-team
Comment: Scheduled maintenance - database migration

Or create regex-based silences
Matchers:
alertname =~ "High.*Usage"
instance =~ "web-[0-9]+\.example\.com"
Duration: 2h
Comment: Load testing in progress

Configure alert templates

Create custom notification templates for better alert messages. Navigate to Alerting > Contact points > Message templates.

Name: detailed-alert-template
Content:
{{ define "alert.title" }}
[{{ .Status | toUpper }}{{ if eq .Status "firing" }} x{{ .Alerts.Firing | len }}{{ end }}] {{ .GroupLabels.alertname }}
{{ end }}

{{ define "alert.summary" }}
{{ if gt (len .Alerts.Firing) 0 }}
Firing Alerts:
{{ range .Alerts.Firing }}
• {{ .Annotations.summary }}
  Labels: {{ range .Labels.SortedPairs }}{{ .Name }}={{ .Value }} {{ end }}
  Started: {{ .StartsAt.Format "2006-01-02 15:04:05 UTC" }}
{{ end }}
{{ end }}

{{ if gt (len .Alerts.Resolved) 0 }}
Resolved Alerts:
{{ range .Alerts.Resolved }}
• {{ .Annotations.summary }}
  Resolved: {{ .EndsAt.Format "2006-01-02 15:04:05 UTC" }}
{{ end }}
{{ end }}

Dashboard: {{ .ExternalURL }}
{{ end }}

Secure webhook endpoints

Add authentication and validation to your webhook endpoints to prevent unauthorized access.

# In webhook contact point configuration
HTTP Headers:
X-Grafana-Source: alerting
User-Agent: Grafana/10.2.3
Authorization: Bearer YOUR-SECRET-TOKEN

Custom headers for verification
X-Signature: {{ .ExternalURL | sha256 }}
X-Timestamp: {{ now.Unix }}

Validate webhook payload

Create a simple webhook receiver to test your configuration.

#!/usr/bin/env python3
import json
import hashlib
import hmac
from http.server import HTTPServer, BaseHTTPRequestHandler

SECRET_TOKEN = "your-secret-token"

class WebhookHandler(BaseHTTPRequestHandler):
    def do_POST(self):
        content_length = int(self.headers['Content-Length'])
        post_data = self.rfile.read(content_length)
        
        # Verify authorization
        auth_header = self.headers.get('Authorization', '')
        if not auth_header.startswith('Bearer '):
            self.send_response(401)
            self.end_headers()
            return
            
        token = auth_header[7:]  # Remove 'Bearer '
        if token != SECRET_TOKEN:
            self.send_response(401)
            self.end_headers()
            return
        
        try:
            alert_data = json.loads(post_data.decode('utf-8'))
            print(f"Received alert: {alert_data['alert_name']}")
            print(f"Status: {alert_data['status']}")
            print(f"Summary: {alert_data['summary']}")
            
            self.send_response(200)
            self.send_header('Content-type', 'application/json')
            self.end_headers()
            self.wfile.write(json.dumps({"status": "received"}).encode())
            
        except json.JSONDecodeError:
            self.send_response(400)
            self.end_headers()

if __name__ == '__main__':
    server = HTTPServer(('localhost', 8080), WebhookHandler)
    print("Webhook test server running on http://localhost:8080")
    server.serve_forever()

Run the test webhook server:

chmod +x /tmp/webhook-test.py
python3 /tmp/webhook-test.py

Create multi-condition alerts

Build complex alerts that require multiple conditions to be met simultaneously.

Rule name: Service Degradation
Folder: Applications
Group: Service Health

Query A - High response time
Query: histogram_quantile(0.95, rate(http_request_duration_seconds_bucket[5m])) * 1000
Alias: response_time_p95

Query B - Error rate
Query: rate(http_requests_total{status=~"5.."}[5m]) / rate(http_requests_total[5m]) * 100
Alias: error_rate

Query C - Request volume
Query: rate(http_requests_total[5m])
Alias: request_volume

Complex condition with AND/OR logic
Expression: ($response_time_p95 > 500 AND $request_volume > 10) OR ($error_rate > 2 AND $request_volume > 5)
Evaluation: Last value, IS ABOVE, 0

Evaluate every: 30s
For: 5m

Configure alert dependencies

Set up alert routing based on dependencies to reduce noise during outages.

# Parent policy - Database connectivity
Matchers:
alertname = "Database Connection Failed"
service = "postgresql"
Contact point: critical-alerts
Group wait: 0s
Repeat interval: 5m

Child policy - Application errors (only if DB is healthy)
Matchers:
alertname = "High Application Error Rate"
NOT database_status = "down"
Contact point: app-team-alerts
Group interval: 10m
Repeat interval: 30m

Silence application alerts when database is down
Matchers:
alertname = "High Application Error Rate"
database_status = "down"
Contact point: null

Create alert annotations with links

Add useful links and context to alert notifications for faster troubleshooting.

# In alert rule annotations
summary: High CPU usage on {{ $labels.instance }}
description: |
  CPU usage: {{ $values.cpu_usage | printf "%.1f" }}%
  Instance: {{ $labels.instance }}
  Environment: {{ $labels.environment }}
  
  🔍 Troubleshooting Links:
  • System Dashboard
  • CPU Details
  • Server Logs,refreshInterval:(pause:!t,value:0),time:(from:now-1h,to:now))&_a=(columns:!(_source),filters:!(('$state':(store:appState),meta:(alias:!n,disabled:!f,index:'logs-*',key:host,negate:!f,params:(query:'{{ $labels.instance }}'),type:phrase),query:(match_phrase:(host:'{{ $labels.instance }}')))))
  • Runbook

runbook_url: https://wiki.example.com/runbooks/high-cpu-usage
dashboard_url: http://grafana.example.com/d/system/system-overview?var-instance={{ $labels.instance }}