Monitoring Azure Event Hubs

Introduction to Monitoring Event Hubs

Monitoring your Azure Event Hubs is crucial for ensuring the health, performance, and reliability of your event streaming pipelines. This guide will walk you through the essential metrics and tools you can use to keep a close eye on your Event Hubs.

Key Monitoring Aspects

Throughput: Track the number of incoming and outgoing messages.
Latency: Measure the delay between sending and receiving events.
Errors: Identify and diagnose any issues with message delivery or consumption.
Resource Utilization: Monitor CPU, memory, and network usage of your Event Hubs.
Consumer Lag: Understand how far behind your consumers are from the latest events.

Azure Monitor for Event Hubs

Azure Monitor is the unified monitoring solution for Azure. It provides comprehensive data for monitoring your Azure resources, including Event Hubs. You can use Azure Monitor to collect, analyze, and act on telemetry from your cloud and on-premises environments.

Metrics

Event Hubs integrates with Azure Monitor to expose a rich set of metrics:

Incoming Messages

Represents the total number of messages sent to Event Hubs. A steady increase indicates successful data ingestion.

Active

Outgoing Messages

Represents the total number of messages retrieved from Event Hubs. Essential for understanding consumer activity.

Active

Captured Messages

Indicates messages that were automatically captured to Azure Blob Storage or Azure Data Lake Storage.

Informational

Requests

Counts the number of HTTP requests made to the Event Hubs service. High request counts might indicate chatty clients.

Monitor

Successful Requests

Number of requests that completed successfully. A drop here could signal issues.

Active

Throttled Requests

Number of requests that were throttled due to exceeding capacity limits. This is a key indicator for performance tuning.

Critical

Client Errors

Number of requests that resulted in client-side errors (e.g., 4xx errors).

Monitor

Server Errors

Number of requests that resulted in server-side errors (e.g., 5xx errors).

Critical

Setting up Dashboards

You can create custom dashboards in Azure Monitor to visualize these metrics. Pin your most important Event Hubs metrics to a dashboard for quick access.


# Example: Pinning metrics to a dashboard (conceptual)
# In Azure Portal:
# 1. Navigate to your Event Hubs namespace.
# 2. Click on "Metrics" under "Monitoring".
# 3. Select desired metrics (e.g., "Incoming Messages", "Throttled Requests").
# 4. Click "Pin to dashboard".

Log Analytics and Kusto Query Language (KQL)

Event Hubs can send diagnostic logs to Log Analytics workspaces. This allows for deeper analysis using Kusto Query Language (KQL).

Common Log Entries

AzureDiagnostics table: Contains operational logs for Event Hubs.
Look for entries related to OperationName, StatusCode, ErrorMessage.

Example KQL Queries

To find throttled requests in the last hour:


AzureDiagnostics
| where ResourceProvider == "MICROSOFT.EVENTHUB" and Category == "ArchiveLogs" and OperationName == "Put"
| where StatusCode startswith "429" // 429 indicates throttling
| summarize count() by bin(TimeGenerated, 5m)
| render timechart

To count client errors:


AzureDiagnostics
| where ResourceProvider == "MICROSOFT.EVENTHUB" and Category == "ArchiveLogs"
| where StatusCode >= 400 and StatusCode < 500
| summarize count() by StatusCode, bin(TimeGenerated, 1h)
| render barchart

Alerting

Set up alerts in Azure Monitor to be proactively notified when specific conditions are met. This is essential for timely intervention.

Alerting Scenarios

High Throttled Requests: Alert when the number of throttled requests exceeds a defined threshold.
Increased Server Errors: Notify if server-side errors spike.
Consumer Lag Detected: If you're using consumer group tracking, alert if lag becomes too high.
Availability Issues: Monitor basic endpoint health.

You can configure alert rules to send notifications via email, SMS, or trigger automated actions like running an Azure Function.

Best Practices for Monitoring

Start Simple: Focus on the most critical metrics first.
Use Dashboards: Consolidate key metrics for easy viewing.
Configure Alerts: Don't wait for problems to arise; set up proactive alerts.
Regular Review: Periodically review your monitoring setup and adjust as needed.
Understand Throughput Limits: Be aware of your Event Hubs tier's capacity to avoid throttling.