Monitoring Azure Virtual Machines

This document provides comprehensive guidance on monitoring your Azure Virtual Machines (VMs) to ensure optimal performance, availability, and security.

Key Takeaway: Effective monitoring is crucial for proactive issue detection and rapid resolution.

Key Monitoring Tools and Services

Azure offers a suite of services designed to provide deep insights into your VM's health and performance:

Azure Monitor

Azure Monitor is the foundational monitoring service for Azure. It collects, analyzes, and acts on telemetry from your cloud and on-premises environments. For VMs, it provides:

Metrics: Numerical values representing performance counters collected at regular intervals (e.g., CPU utilization, disk I/O, network traffic).
Logs: Event data from operating systems and applications, which can be queried and analyzed for troubleshooting and diagnostics.
Application Insights: For application performance monitoring (APM) within your VMs.
Container insights: For monitoring containerized applications running on VMs.

Log Analytics

A key component of Azure Monitor, Log Analytics allows you to query and analyze log data. You can write powerful queries to identify trends, diagnose problems, and gain operational insights.

Common log sources for VMs include:

Windows Event Logs
Linux Syslog
IIS Logs
Custom application logs

Application Insights

While often used for PaaS services, Application Insights can be integrated with applications running on your Azure VMs to provide:

Request rates, response times, and failure rates
Performance bottlenecks
Exception tracking
End-to-end transaction tracing

Configuring VM Monitoring

Enabling Azure Monitor for VMs

To leverage Azure Monitor, you typically need to:

Install the Azure Monitor Agent: This agent collects data from your VMs and sends it to Azure Monitor.
Configure Data Collection Rules: Define which metrics and logs to collect and where to send them (e.g., Log Analytics workspace).

Setting Up Alerts

Alerts notify you when specific conditions are met, allowing for timely intervention.

You can set up alerts based on:

Metric Alerts: Trigger when a metric crosses a predefined threshold (e.g., CPU usage > 90% for 15 minutes).
Log Alerts: Trigger when the results of a Log Analytics query match certain criteria.
Activity Log Alerts: Monitor Azure resource events.

Alerts can be configured to send notifications via email, SMS, or trigger automated actions like running a webhook or Azure Function.

Best Practices for VM Monitoring

Define Key Performance Indicators (KPIs): Identify the metrics most critical to your application's health and user experience.
Establish Baseline Performance: Understand what normal performance looks like for your VMs to easily spot anomalies.
Implement Comprehensive Logging: Ensure your VMs are logging relevant events and errors from both the OS and applications.
Configure Meaningful Alerts: Avoid alert fatigue by setting up alerts only for critical conditions that require immediate attention.
Regularly Review Monitoring Data: Don't just set and forget. Periodically analyze your metrics and logs to identify potential issues and areas for optimization.
Leverage Resource Health: Azure Resource Health provides information about service issues that may affect your resources.

Example: Monitoring CPU Usage

To monitor CPU usage, you would typically enable the Percentage CPU metric for your VM. You could then configure an alert rule that triggers if the average CPU usage exceeds 80% for more than 10 minutes.

-- Example Log Analytics query to find VMs with high CPU
VMProcess
| where PercentProcessorTime > 80
| summarize avg(PercentProcessorTime) by Computer, bin(TimeGenerated, 5min)
| order by avg_PercentProcessorTime desc