Learn the things to know about Azure Monitor Logs

Azure Monitor Logs is a powerful feature of Azure Monitor designed to collect, analyze, and query log data from Azure resources, on-premises environments, and third-party services. Here’s what you need to know:

What Are Logs?

Definition:

Logs are detailed, text-based records of events and activities, often used for troubleshooting and auditing.

Types of Logs:

1. Activity Logs: Record operations on Azure resources (e.g., who created a VM).

2. Diagnostic Logs: Provide performance, health, and error details for Azure resources.

3. Telemetry Logs: Custom logs from applications (via Application Insights).

4. Audit Logs: Track compliance and governance-related activities.

Log Analytics Workspace

1. Central Repository: Logs are stored in a Log Analytics Workspace for analysis and querying.

2. Multi-Resource Logs: A single workspace can collect data from multiple resources across Azure and hybrid environments.

3. Cost Control: Pricing depends on data ingestion and retention; you can customize retention policies.

Querying Logs with KQL (Kusto Query Language)

Purpose:

KQL is used to analyze log data efficiently.

Features:

1. Filtering, sorting, and aggregating log data.

2. Advanced operations like joins, unions, and time-series analysis.

Example Query:

1
AzureActivity
2
| where ActivityStatus == "Failed"
3
| summarize Count = count() by ResourceGroup, bin(Timestamp, 1h)
4
| order by Count desc

Key Features

1. Data Collection Collect logs from Azure services, virtual machines, and custom applications. Integrate with on-premises systems using agents or Azure Arc.

2. Visualization Build rich visualizations in Azure Workbooks or export data to Power BI. Combine logs with metrics for a unified view.

3. Alerts Configure log-based alerts using queries (e.g., when error logs exceed a threshold).

4. Integration Export logs to Event Hubs for streaming or to external systems like Splunk. Use with Azure Sentinel for security analytics.

Common Use Cases

1. Troubleshooting: Diagnose issues by analyzing logs for errors, exceptions, and latency.

2. Performance Monitoring: Understand resource usage trends and application performance.

3. Compliance and Auditing: Track and audit user actions and system changes.

4. Security Monitoring: Detect anomalies and suspicious activities using custom queries.

Supported Data Sources

1. Azure Resources: Virtual machines, App Services, Azure Kubernetes Service (AKS), etc.

2. Custom Applications: Collect logs using Application Insights SDKs.

3. Third-Party Sources: Use APIs or Event Hubs to ingest data from external systems.

Retention and Export

1. Retention Policies: Default retention is 31 days (customizable up to 730 days with extra costs).

2. Export Options: Export logs to storage accounts, Event Hubs, or external systems. Use the Continuous Export feature for real-time log streaming.

Cost Considerations

Costs are based on:

1. Data Ingestion: Amount of data sent to the Log Analytics Workspace.

2. Data Retention: Duration for which logs are retained.

Optimize costs by filtering unnecessary logs or reducing retention duration.

Security and Compliance

1. Data Security: Logs are encrypted at rest and in transit. Role-Based Access Control (RBAC) restricts access to sensitive data.

2. Compliance: Azure Monitor Logs adheres to standards like ISO, GDPR, and HIPAA.

Best Practices

1. Define Clear Data Collection Policies: Enable logging only for critical resources to avoid excessive costs.

2. Organize Workspaces: Use separate Log Analytics Workspaces for different teams or projects.

3. Leverage Queries and Alerts: Use KQL queries to create actionable alerts and reports.

4. Combine Logs with Metrics: Use both logs and metrics for a comprehensive monitoring strategy.

5. Visualize Trends: Build workbooks and dashboards for insights tailored to your needs.

Getting Started

1. Set up a Log Analytics Workspace in the Azure portal.

2. Configure Diagnostic Settings for resources to send logs to the workspace.

3. Use Log Analytics to write and execute KQL queries.

4. Create visualizations, alerts, or export options based on your logs.

Summary

Azure Monitor Logs enables deep visibility and actionable insights into your infrastructure and applications, helping you maintain optimal performance, ensure compliance, and quickly resolve issues.