Monitoring Azure Traffic Manager

This document provides a comprehensive guide on how to monitor the performance and health of your Azure Traffic Manager profiles.

Introduction

Azure Traffic Manager is a DNS-based traffic load balancer that enables you to distribute traffic optimally to your services in different Azure regions or even to external endpoints. Effective monitoring is crucial for ensuring high availability, performance, and timely issue detection.

Key Monitoring Metrics

Traffic Manager exposes several key metrics that are vital for understanding its behavior:

DNS Queries: The number of DNS requests received by your Traffic Manager profile. High query volume can indicate significant user traffic.
Endpoint Health: The status of each endpoint configured in your Traffic Manager profile (e.g., online, degraded, offline).
Latency: The DNS query latency experienced by users.
Failover Events: Records of Traffic Manager automatically failing over traffic from a unhealthy endpoint to a healthy one.

Monitoring Tools and Techniques

Azure Monitor

Azure Monitor is the primary service for collecting, analyzing, and acting on telemetry from your Azure and on-premises environments. You can use Azure Monitor to:

View Metrics: Access Traffic Manager metrics directly within the Azure portal.
Set Alerts: Configure alerts based on metric thresholds (e.g., if an endpoint becomes unhealthy or DNS query volume exceeds a certain level).
Create Dashboards: Build custom dashboards to visualize key metrics for your Traffic Manager profiles alongside other Azure services.
Use Logs: Analyze diagnostic logs for detailed information about Traffic Manager operations and events.

Accessing Traffic Manager Metrics in Azure Monitor:

Navigate to the Azure portal.
Search for and select "Traffic Manager profiles".
Choose the Traffic Manager profile you want to monitor.
Under the "Monitoring" section, select "Metrics".

Diagnostic Settings

Configure diagnostic settings for your Traffic Manager profile to send logs and metrics to various destinations:

Log Analytics Workspace: For advanced querying and analysis using Kusto Query Language (KQL).
Storage Account: For long-term archival of logs.
Event Hubs: For integrating with other monitoring solutions or real-time processing.

Configuring Diagnostic Settings:

In your Traffic Manager profile blade, navigate to "Diagnostic settings" under "Monitoring".
Click "Add diagnostic setting".
Select the categories of logs and metrics you want to send. For Traffic Manager, common categories include AllMetrics and TrafficFlow.
Choose the destination(s) where you want to send the data.
Click "Save".

Kusto Query Language (KQL) for Log Analysis

When using Log Analytics, KQL is essential for querying diagnostic logs. Here are some example queries:

Example 1: View recent DNS query logs

TrafficManagerEndpointMetrics_CL
| where TimeGenerated > ago(1h)
| where MetricName_s == "DNSQueries"
| project TimeGenerated, ProfileName_s, EndpointName_s, Value
| sort by TimeGenerated desc

Example 2: Identify endpoints that have gone offline

TrafficManagerEndpointStatusEvents_CL
| where TimeGenerated > ago(24h)
| where EndpointStatus_s == "Degraded" or EndpointStatus_s == "Unhealthy"
| project TimeGenerated, ProfileName_s, EndpointName_s, EndpointStatus_s, PreviousStatus_s
| sort by TimeGenerated desc

Best Practices for Monitoring

Set up comprehensive alerts: Don't just monitor; be alerted proactively when issues arise.
Regularly review dashboards: Gain a quick overview of your Traffic Manager health and performance.
Understand your baseline: Know what normal traffic patterns and response times look like to quickly spot anomalies.
Monitor endpoint health: Ensure that Traffic Manager is correctly reporting the status of your services.
Correlate with other metrics: View Traffic Manager metrics alongside metrics from your backend services for a holistic view.

Tip: Consider using Azure Application Insights for deep monitoring of your applications hosted behind Traffic Manager. This provides insights into application performance, errors, and dependencies.

Troubleshooting Common Issues

If you encounter issues:

Check endpoint status: Verify if Traffic Manager correctly identifies endpoints as unhealthy.
Examine diagnostic logs: Look for specific error messages or patterns.
Test DNS resolution: Use tools like nslookup or dig from various locations to test how Traffic Manager is resolving DNS.
Verify probing configurations: Ensure that the health probes configured for your endpoints are accurate and accessible.

Traffic Manager Health Probe Settings

The health probe configuration directly impacts how Traffic Manager determines endpoint availability. Key settings include:

Setting	Description
Protocol	HTTP, HTTPS, or TCP.
Port	The port to use for the probe (e.g., 80 for HTTP, 443 for HTTPS).
Path	For HTTP/HTTPS probes, the relative path to probe on the endpoint.
Interval	The time between probes (e.g., 30 seconds).
Timeout	The timeout for each probe (e.g., 5 seconds).
Tolerated number of failures	The number of consecutive failures before an endpoint is marked unhealthy.

Conclusion

By leveraging Azure Monitor, diagnostic settings, and understanding key metrics, you can effectively monitor your Azure Traffic Manager profiles. This ensures that your applications remain available and performant for users worldwide.