Azure Log Analytics Alerts

Introduction to Log Analytics Alerts

Azure Log Analytics alerts enable you to proactively identify and respond to critical issues in your applications and infrastructure. By defining specific conditions based on your log data, you can trigger notifications or automated actions when those conditions are met.

This guide will walk you through the process of creating, managing, and optimizing alerts within Azure Log Analytics, ensuring you have full visibility into the health and performance of your resources.

Key Concepts

Creating an Alert Rule

You can create alert rules directly from the Azure portal or programmatically using Azure CLI, PowerShell, or ARM templates.

Using the Azure Portal

1. Navigate to your Log Analytics workspace.
2. Under the Monitoring section, select Alerts.
3. Click on + New alert rule.
4. Select resource: Choose the Log Analytics workspace you want to monitor.
5. Add condition:
   • Select the Signal type (e.g., Log Search).
   • Write a Kusto Query Language (KQL) query to define your condition.
   • Configure the Measurement (e.g., count of records) and the Alert logic (e.g., threshold).
   • Set the Evaluation frequency and Lookback period.
6. Select action group: Choose an existing action group or create a new one to define notifications and actions.
7. Configure details:
   • Provide an Alert rule name.
   • Set the Severity.
   • Add a Description.
   • Configure Custom properties if needed.
8. Review and create: Confirm your settings and create the alert rule.

Example KQL Query for Alerting

This example triggers an alert if more than 100 'Error' events occur within 5 minutes:

Event
| where Level == "Error"
| summarize count() by bin(TimeGenerated, 5m)
| where count_ > 100
            

Managing Alerts

The Alerts blade in your Log Analytics workspace provides a centralized view of all triggered alerts. You can:

• View triggered alerts: See a history of alerts, their status, and details.
• Acknowledge alerts: Mark alerts as acknowledged to indicate that they are being investigated.
• Resolve alerts: Mark alerts as resolved once the issue has been fixed.
• Edit alert rules: Modify existing alert rules as your monitoring needs evolve.
• Delete alert rules: Remove alert rules that are no longer necessary.

Understanding Alert States

• New: The alert has been triggered and has not yet been acknowledged or resolved.
• Acknowledged: The alert has been acknowledged by a user, indicating that it is being investigated.
• Resolved: The condition that triggered the alert is no longer met, or the alert has been manually resolved.

Best Practices for Alerts

• Be specific: Craft clear and precise KQL queries to avoid noisy or false positive alerts.
• Set appropriate severity: Assign the correct severity level to help prioritize responses.
• Use Action Groups effectively: Configure action groups to ensure notifications reach the right people or systems.
• Regularly review alert rules: As your applications and infrastructure change, update your alert rules to remain relevant.
• Monitor alert fatigue: Avoid overwhelming your team with too many alerts. Tune your rules to focus on actionable insights.
• Integrate with ITSM tools: Connect your alerts to incident management systems for streamlined workflows.

Advanced Alerting Scenarios