This document provides an overview of Windows Azure Diagnostics (WAD). WAD allows you to monitor and diagnose issues with Azure instances by capturing diagnostic data like logs and transferring it to Azure storage. It has an agent that runs on each instance and pulls a configuration specifying what data to capture and store. This captured data is transferred on a schedule to Azure storage like tables and blobs. The tool also allows on-demand transfers and custom logging. It can be managed through code to modify the configuration per instance.

1. Windows Azure Diagnostics
Neil Mackenzie

2. Overview
• Motivation for Windows Azure Diagnostics
• Architecture of WAD
• Configuring WAD
• Managing WAD
• Demonstration

3. Why Windows Azure Diagnostics?
WAD Provides:
• visibility into instance VMs
• access to IIS logs, event logs and traces
• configuration of diagnostic information captured
• consistent way to persist diagnostic information
WAD Supports:
• non-intrusive investigation of problems
• auto-scaling through access to performance counters
IntelliTrace

4. WAD Architecture
Diagnostics Agent
• Runs on each instance
• Persists diagnostic data to Azure Storage
Configuration
• Instance-specific WAD configuration
• Located in an Azure Blob container
• Polled by Diagnostics Agent
Azure Storage
• WAD uses blobs, tables and queues
.NET API

5. Configuration
WAD Configuration
• Instance-specific blobs in wad-control-container
WAD Configuration specifies:
• data buffers to be captured
• data buffers to be persisted
• transfer schedule
WAD .NET API updates WAD configuration
Diagnostics Agent:
• polls WAD configuration to identify changes.
• implements changes

6. Data Buffers
WAD captures data to the data buffer
WAD persists data to the Azure Storage location
Data Buffer Azure Storage Location
Windows Azure logs * WADLogsTable
Windows Diagnostic infrastructure logs * WADDiagnosticsInfrastructureLogsTable
IIS 7.0 logs (webrole) * wad-iis-logfiles (blobs)
Failed Request logs (webrole) wad-iis-failedreqlogfiles (blobs)
Windows Event logs WADWindowsEventLogsTable
Performance counters WADPerformanceCountersTable
Crash dumps wad-crash-dumps (blobs)
Custom error logs Configurable (blobs)
* Captured by default
WADDirectoriesTable contains one entity for each blob stored by WAD

7. Custom Logging
WAD supports custom logging
Configure:
• Capture directory in local storage
• Persistence location in Azure Blob storage
• Transfer schedule

8. Persistence
Scheduled Transfers
• Routine transfers to persistent storage
• Transfer period specific to a data buffer
On-Demand Transfers
• Immediate need to persist data
• Possibility of duplicate data in persistent storage
Cleanup
• WAD does not cleanup persisted data
• Should not delete the tables/containers

9. Managing WAD
Diagnostics Agent started automatically
• Default configuration
WAD managed on a per-instance basis
• Use RoleInstanceDiagnosticManager
• Get WAD configuration for instance
• Modify WAD configuration
• Set current WAD configuration for the instance

10. On-Demand Transfers
On-Demand transfers configured for:
• Instance
• Data buffer
Use RoleInstanceDiagnosticManager
• Configure on-demand transfer
• Request on-demand transfer
Cleanup on-demand transfer
• Get completion message from WAD notification queue
• End on-demand transfer
One on-demand transfer per data buffer

11. Tools
Cerebrata
• Azure Diagnostics Manager
Microsoft
• Systems Center Operations Manager – Windows
Azure Management Pack RC

12. Demo
Web role with two instances demonstrating
various aspects of Windows Azure Diagnostics

13. Contact Information
• Neil Mackenzie
• Twitter: @mknz
• Blog: http://convective.wordpress.com/