1. DevOps – Desired State Configuration –
Mohit K. Gupta
DevOps – Desired State Configuration –

2. SQL Summit Annual International Conference November 6 -9 | Seattle, WA
2 Days of Pre-Cons
200+ sessions over 3 days
Over 5,000 SQL Professionals
Evening Networking Activities

3. Please Support Our Sponsors

4. Let’s Not Distract Others
Please silent your phone
We can chat later
Please don’t snore

5. Agenda Introduction to Desired State Configuration (DSC) Requirements
DSC v4 and DSC v5
DSC Terminology
Development & Deployment
DSC Resources

6. Introduction

7. Introduction DSC is a configuration management platform
Service and Application Agnostic
Standards-based
Distributed
Benefits
Ensures configuration
Supports continuous deployment
Prevents configuration drift
Change control becomes a text file

8. Challenge 1: Deployment & Consistency
Manual deployment is neither repeatable nor consistent
Dev, Test, Prod do not match
Build scripts can break mid-stream

9. Challenge 2: Server Outage
Change happened somewhere
Configuration drift

10. Imperative vs Declarative Language
Add-WindowsFeature Windows-Server-Backup
Declarative
Configuration BaseBuild {
WindowsFeature Backup {
Ensure = "Present"
Name = "Windows-Server-Backup" }

11. Requirements

12. Operating System Requirements
WMF 4.0
WMF 5.0
Windows 7
Upgrade
Windows 2008 R2
Windows 8
Windows 2012
Windows 8.1
Default
Windows 2012 R2
Windows 10
Windows 2016
PowerShell DSC requires .NET Framework 4.5

13. Windows 2008 R2 Compatibility
Supports PowerShell DSC via WMF 4.0 or WMF 5.0 update
Built-in resources will work
Limited support for community resources

14. DSC v4 and DSC v5

15. DSC Command-Lets by Version
Name
DSC v4
DSC v5
Configuration X
Get-DscConfiguration
Get-DscLocalConfigurationManager
Get-DscResource
New-DscCheckSum
Restore-DscConfiguration
Test-DscConfiguration
Set-DscLocalConfigurationManager
Start-DscConfiguration
Remove-DscConfigurationDocument
Stop-DscConfiguration
Update-DscConfiguration
Find-DscResource
Get-DscConfigurationStatus
Invoke-DscResource
Publish-DscConfiguration
Enable-DscDebug
Disable-DscDebug

16. Demonstration - Deploy SQL Server -

17. DSC Terminology

18. Terminology Configuration File Built-In Resources MOF
Local Configuration Manager
Push / Pull

19. Configuration File Configuration IISWebsite { Node Server1
WindowsFeature IIS
Ensure = "Present"
Name = "Web-Server" }
WindowsFeature ASP
Name = "Web-Asp-Net45"

20. Built-In Resources File Archive Environment Group Log Package Registry
Script
Service
User
WindowsFeature
WindowsProcess

21. MOF File MOF – Managed Object Format
Industry standard text file contain resource and configuration data.
Consumed by WMI/CIM.
localhost.mof

22. Local Configuration Manager (LCM)
The “DSC engine”
Enforces configuration and consistency
Can auto-correct a state that changes
Settings to configure intervals, reboots, etc.
Local Configuration Manager

23. LCM Properties Get-DscLocalConfigurationManager ConfigurationMode
ApplyOnly
ApplyAndMonitor (Default)
ApplyAndAutoCorrect
ConfigurationModeFrequencyMins
Interval to apply configuration
RefreshFrequencyMins
Interval to pull configuration
RefreshMode
Push
Pull
Disabled

24. Push / Pull Authoring Staging Nodes Config Pulled IIS Config Pulled
Server1
Config Pushed
Config Pulled
Server1.mof
Server1
Configs Deployed
Server1.mof
Config Pulled
IIS
Server1.mof
Server1
Configs Deployed
Server1.mof
File Share

25. LCM Example - Pull [DscLocalConfigurationManager()]
Configuration LCMPull {
Node localhost
Settings
ActionAfterReboot = 'ContinueConfiguration'
AllowModuleOverWrite = $True
ConfigurationID = 'a019aeb4-27e0-4ae2-b2f9-edc0fc620338'
ConfigurationMode = 'ApplyAndAutoCorrect'
ConfigurationModeFrequencyMins = 15
RefreshFrequencyMins = 30
StatusRetentionTimeInDays = 7
RebootNodeIfNeeded = $True
RefreshMode = 'Pull' }
ConfigurationRepositoryWeb PullServer
ServerURL = "
AllowUnsecureConnection = $false

26. LCM Example - Push [DscLocalConfigurationManager()]
Configuration LCMPushv5 {
Node localhost
Settings
ActionAfterReboot = 'ContinueConfiguration'
AllowModuleOverWrite = $True
ConfigurationMode = 'ApplyAndAutoCorrect'
ConfigurationModeFrequencyMins = 15
RefreshFrequencyMins = 30
StatusRetentionTimeInDays = 7
RebootNodeIfNeeded = $True
RefreshMode = 'Push' }
LCMPushv5
Set-DSCLocalConfigurationManager -Path .\LCMPushv5

27. Development & Deployment

28. Quick Configuration – Snippets & Syntax
CTRL + J snippet for configuration.
Get-DscResourceName -Syntax
Copy and Paste

29. Quick Configuration - IntelliSense
Type the resource name and curly braces.
CTRL+SPACE for IntelliSense.
Use TAB completion for enumerated property values and DependsOn.

30. Quick Configuration - DependsOn
Configuration DependsOnExample {
Import-DscResource -ModuleName PSDesiredStateConfiguration
Node localhost {
File DSCTempFolder {
DestinationPath = 'C:\DSCTemp\'
Ensure = 'Present'
Type = 'Directory' }
Archive ExtractZIP {
Path = 'C:\InstallSource\LogParser.zip'
Destination = 'C:\DSCTemp\logparser\'
Force = $true
DependsOn = '[File]DSCTempFolder'
Package InstallLogParser {
Ensure = 'Absent'
Name = 'Log Parser 2.2'
Path = 'C:\DSCTemp\logparser\logparser.msi'
ProductId = '4AC23178-EEBC-4BAF-8CC0-AB15C8897AC9'
DependsOn = '[Archive]ExtractZIP'
The order of execution of resources is not guaranteed.
Use the common property DependsOn to establish order in the format [Resource]Name.

31. Start-DscConfiguration
C:\Windows\System32\Configuration\
Start-DscConfiguration
publishes and applies pending.mof
2. Renames current to previous
previous.mof
current.mof
pending.mof
3. Renames pending to current

32. Start-DscConfiguration -UseExisting
1. Reapplies current.mof
previous.mof
current.mof

33. Restore-DscConfiguration
previous.mof
current.mof
pending.mof
1. PUSH mode only.
Renames previous to pending

34. Remove-DscConfigurationDocument
Remove-DscConfigurationDocument -Stage Current
Pending
Previous
previous.mof
current.mof
pending.mof
Used to “unconfigure” DSC configuration, leaving the settings applied.

35. Query the Desired State
Test-DscConfiguration – true/false desired state
Get-DscConfiguration – current state of configured resources
Get-DscConfigurationStatus – Date & time, success or failure
Get-DscConfigurationStatus -All – History of DSC events and status

36. DSC Resources

37. Resources
A resource is PowerShell code that tells a node how to configure the settings
Use property values as parameters
Can express dependencies
Deployed using PowerShell modules

38. Resource Types Built-In Resource Kit(s)
Community (ex. TechNet Script Center, GitHub)
Custom

39. Key Command Lets Command Let Description Get-DscResource
Shows current installed resources on system. Can also be used to determine the resource syntax.
Find-DscResource
Find-Module
Search for repositories online.
Install-Module
Save-Module
Install the DSC Resource.

40. Resource Naming Conventions
Resource Name
Meaning
[ ]FileSystem
This resource or other like it are built-in resources with no-prefix.
[x]SQLServer
Microsoft DSE Resource Kit, stands for eXperimental. Developed by Microsoft.
[c]ResourceName
Community Developed.

41. Questions?