This is a London Windows Azure Group Presentation for December 11 on Diagnostics in Windows Azure

2. Windows Azure Diagnostics
Andy Cross

3. Overview
• Diagnostics in Windows Azure
– Application Level
– Service Level
– Operating System Level
• Things your application chooses to log
App
• Things logged by what runs your application
Service
• Things logged by OS container
OS

4. Example Log Usage
• Application:
– Error: Cannot save Order
• Service:
– Error: IO Exception
• OS:
– Error: Disk is full

5. What’s special?
• Familiar diagnostic challenges
– Already solved on premises
• Massively scalable
– No request affinity
– Unpredictable application topology
• Where do the logs go?!
– Centralised Logging approach

6. What you need
• Hosted Service:
– Compute capacity within Windows Azure
• Storage Account:
– Storage capacity within Windows Azure
• Table
• Blobs

7. Windows Azure Diagnostics
My Azure
Hosted Service App
Worker
Role Web Role
Role
Instances IN_0 IN_1 IN_0
• Each Role
– Configurable Diagnostics Monitor
– Each Instance inherits configuration

8. Example Trace Points
• Application
– .net application Tracing
– custom
• Files written via nLog, log4net etc
– Windows Event Log
• Service
– IIS Logs
– IIS Failed Request Logs
– Azure Diagnostics Infrastructure Logs
• Metalog
– Performance Counters
• Operating System
– Windows Event Log
– Custom (any known file log)

9. Configuration
• Set options on types
– Directories
– Logs
– Performance Counters
• Storage Options
– Some types allow a configurable destination
• Transfer Period
• Maximum Buffer Size

10. Transfer
• Two distinct methods of transfer
– Same underlying result
• On Demand Transfer
• Scheduled Transfer

11. Output formats
Type Description Destination
Trace With Trace Listener Table WADLogsTable
IIS Logs W3svc format Blob
Windows Event Logs Table WADWindowsEventLogsTable
Windows Performance Table WADPerformanceCountersTable
Counters
Custom Logs File based Blob
Crash Dump Blob
Diagnostic Infrastructure Metalog Table WADDiagnosticInfrastructureLogsTable
Log

12. Methodologies
• .net Tracing
– Add Trace Listener
– Configure WAD
– View Result:

13. Logging per Instance
• Logs on Instance Basis:
– RoleInstance:
• deployment(526).MultipleTraceSources.Host_IN_0
– DeploymentId.Role.Instance
• Allows for per instance diagnosis

14. Configure Windows Azure Diagnostics
• Setup Storage Account
• Create Role Instance Diagnostics Manager
• Get and update a configuration from Manager
• Set Current Configuration

15. Example Code

16. Extended Code

17. Verbosity
• Code is building XML WADCFG
– Structure based on XML Schema
• Not necessarily intuitive

18. Fluent Diagnostics
• Attempts to curtail verbosity

19. Windows Azure Role Lifecycle
• Each Role runs
– OnStart
– Run
– OnStop
• Setup Diagnostics OnStart – always correct for
that role
• But if you change the config, another OnStart
will undo your changes

20. Change at Runtime
• WAPPSCmdlets
PowerShell cmdlets available at wappowershell.codeplex.com
Example courtesy of michaelwasham.com

21. Diagnostics Lifecycle
Scenario A
Diagnostics A Diagnostics A
OnStart Run Redeploy OnStop OnStart Run
Diagnostics B

22. Diagnostics Lifecycle
Scenario B
Diagnostics A Diagnostics A
Change
OnStart Run Instance OnStart Run
Count
Diagnostics B

23. Diagnostics Lifecycle
• Why do we see this behaviour?
– Increase Instance Count
– New Instance added by Fabric
– Instance goes through OnStart!

24. Fluent Diagnostics
• Allows you to use programmatic approach still
– Uses Marker XML
– Prevents further updates for a deployment

25. Diagnostics Lifecycle
Fluent Diagnostics Scenario B
Diagnostics A Marker File Added Diagnostics A
Change
OnStart Run Instance OnStart Run
Count
Diagnostics B

26. How to view Diagnostics
• Raw in Tables, as shown before.
• Cerebrata Azure Diagnostics Manager

27. Q&A
• Many thanks.
• Check out my blog:
http://blog.bareweb.eu
• Questions and Answers session