YAML Templates

Azure DevOps pipelines use YAML to define build and release workflows in a human- and machine-readable format. In this guide, we’ll explore YAML essentials, step through an ASP.NET pipeline example, and demonstrate how to leverage templates for reusable CI/CD components.

YAML is both concise and clear, making it ideal for version-controlled CI/CD definitions. Learn more at the YAML Official Site.

Example: ASP.NET CI/CD Pipeline

Use the following ASP.NET pipeline to build, test, and package your web application. For full task details, see the Azure DevOps ASP.NET docs.

trigger:
  - master

pool:
  vmImage: 'windows-latest'
  name: 'Default'

variables:
  solution: '**/*.sln'
  buildPlatform: 'Any CPU'
  buildConfiguration: 'Release'

steps:
  - task: NuGetToolInstaller@1

  - task: NuGetCommand@2
    inputs:
      restoreSolution: '$(solution)'

  - task: VSBuild@1
    inputs:
      solution: '$(solution)'
      msbuildArgs: >-
        /p:DeployOnBuild=true
        /p:WebPublishMethod=Package
        /p:PackageAsSingleFile=true
        /p:SkipInvalidConfigurations=true
        /p:PackageLocation="$(build.artifactStagingDirectory)\$(Build.BuildId).zip"
      platform: '$(buildPlatform)'
      configuration: '$(buildConfiguration)'

  - task: VSTest@2
    inputs:
      platform: '$(buildPlatform)'
      configuration: '$(buildConfiguration)'

Starter Pipeline

Begin with a minimal YAML pipeline and customize it for your project:

trigger:
  - master

pool:
  vmImage: 'ubuntu-latest'
  name: 'Default'

steps:
  - script: echo Hello, world!
    displayName: 'Run a one-line script'

  - script: |
      echo Add other tasks to build, test, and deploy your project.
      echo See https://aka.ms/yaml
    displayName: 'Run a multi-line script'

Key elements:

trigger: Events that kick off the pipeline.
pool: Agent selection (e.g., ubuntu-latest).
steps: Tasks or scripts to execute in sequence.

Viewing a Pipeline Run

A typical Azure DevOps pipeline run reveals build warnings, repository info, branch, and elapsed time:

The image shows an Azure DevOps pipeline run summary with warnings related to possible null reference dereferences in the code. It includes details like the repository, branch, and time elapsed.

Creating a New Pipeline

When you create a pipeline, select your source—Azure Repos Git, Bitbucket Cloud, GitHub, or GitHub Enterprise—and choose the Starter Pipeline for IntelliSense support:

The default YAML appears:

trigger:
  - master

pool:
  vmImage: 'ubuntu-latest'
  name: 'Default'

steps:
  - script: echo Hello, world!
    displayName: 'Run a one-line script'
  - script: |
      echo Add other tasks to build, test, and deploy your project.
      echo See https://aka.ms/yaml
    displayName: 'Run a multi-line script'

Validate and run to see output:

Starting: Run a one-line script
> echo Hello, world!
  Hello, world!

YAML Structure Basics

YAML relies on three core constructs: key–value pairs, lists, and nested mappings. Use indentation for hierarchy and avoid tabs.

Syntax Type	Description	Example
Key–value pair	Maps a key to a single value	`trigger: [master]`
List	Defines an ordered sequence	`fruits: [Apple, Banana, Cherry]`
Nested mapping	Embeds mappings under a parent key	`pool:\n vmImage: ubuntu-latest\n name: Default`

Examples: Key–value pair:

trigger:
  - master

List:

fruits:
  - Apple
  - Banana
  - Cherry

Nested mapping:

pool:
  vmImage: ubuntu-latest
  name: Default

Variables and Overrides

Define pipeline variables at the top and allow runtime overrides:

variables:
  solution: '**/*.sln'
  buildPlatform: 'Any CPU'
  buildConfiguration: 'Release'
  pipelineRunnerName: 'DefaultUser'
  pipelineRunnerAge: 30

steps:
  - script: echo Hello, $(pipelineRunnerName)!
    displayName: 'Greet runner'
  - script: echo Runner age is $(pipelineRunnerAge)
    displayName: 'Show runner age'

Users can override pipelineRunnerName and pipelineRunnerAge on the Run Pipeline screen. Ensure correct defaults to avoid unexpected behavior.

Best Practices

Leverage comments to clarify intent.
Keep pipelines DRY by defining reusable variables and templates.
Organize common logic into separate files.

Applying Templates

Break out common steps into parameterized or extendable templates. Example templates: nuget.yml

steps:
  - task: NuGetToolInstaller@1
  - task: NuGetCommand@2
    inputs:
      command: 'restore'
      restoreSolution: '$(solution)'

build.yml

steps:
  - task: VSBuild@1
    inputs:
      solution: '$(solution)'
      msbuildArgs: >-
        /p:DeployOnBuild=true
        /p:WebPublishMethod=Package
        /p:PackageAsSingleFile=true
        /p:SkipInvalidConfigurations=true
        /p:PackageLocation="$(build.artifactStagingDirectory)"
      platform: '$(buildPlatform)'
      configuration: '$(buildConfiguration)'

test.yml

steps:
  - task: VSTest@2
    inputs:
      platform: '$(buildPlatform)'
      configuration: '$(buildConfiguration)'

Reference templates in your main pipeline (azure-pipelines.yml):

trigger:
  - master

pool:
  vmImage: 'ubuntu-latest'
  name: 'Default'

variables:
  solution: '**/*.sln'
  buildPlatform: 'Any CPU'
  buildConfiguration: 'Release'
  pipelineRunnerName: 'DefaultUser'
  pipelineRunnerAge: 30

steps:
  - script: echo Hello, $(pipelineRunnerName)!
    displayName: 'Greet runner'

  - template: 'nuget.yml'
  - template: 'build.yml'
  - template: 'test.yml'

Build and Test Summaries

After applying templates, review your build results in the pipeline summary:

The image shows an Azure DevOps pipeline run summary with details about a specific build, including warnings related to null reference dereferencing. The build is triggered by a user and shows test results and code coverage.

Monitor recent runs and their status:

The image shows an Azure DevOps pipeline interface with a list of recent pipeline runs for "KodeKloudData," each marked with a green check indicating successful completion.

Check detailed logs to confirm test success:

The image shows an Azure DevOps pipeline run with a list of completed jobs, all marked as successful, and a log indicating that 100% of tests passed.

Conclusion

Azure DevOps YAML templates enable modular, maintainable CI/CD pipelines. You’ve learned:

Core YAML syntax and structure
Defining variables and overrides
Extracting and reusing templates
Reviewing build and test outcomes

Experiment with these patterns to streamline your Azure DevOps workflows.

Links and References

Watch Video

Implementing Release Gates

Summary

Introduction

Configure Activity Traceability and Flow of Work

Configure Collaboration & Communication

Work with Azure Repos and GitHub

Configuring and Managing Repositories

Design and Implement Pipeline Automation

Design and Implement Pipelines

Implementing an Orchestration Automation Solution

Design and Implement Deployments

Design and Implement Infrastructure as Code (IaC)

Maintain Pipelines

Design and Implement Authentication and Authorization Methods

Design and Implement a Strategy for Managing Sensitive Information in Automation

Implement Security and Validate Code Bases for Compliance

Configure Monitoring for a DevOps Environment

Analyze Metrics

Branching Strategies for Source Code

Design and Implement a Package Management Strategy

Example: ASP.NET CI/CD Pipeline

Starter Pipeline

Viewing a Pipeline Run

Creating a New Pipeline

YAML Structure Basics

Variables and Overrides

Best Practices

Applying Templates

Build and Test Summaries

Conclusion

Links and References

Watch Video

​Example: ASP.NET CI/CD Pipeline

​Starter Pipeline

​Viewing a Pipeline Run

​Creating a New Pipeline

​YAML Structure Basics

​Variables and Overrides

​Best Practices

​Applying Templates

​Build and Test Summaries

​Conclusion

​Links and References

Watch Video

Example: ASP.NET CI/CD Pipeline

Starter Pipeline

Viewing a Pipeline Run

Creating a New Pipeline

YAML Structure Basics

Variables and Overrides

Best Practices

Applying Templates

Build and Test Summaries

Conclusion

Links and References