The pipeline: a file, not a folktale.

You can read azure-pipelines.yml a dozen times and still not know what happens when a merge fires it, an agent picks it up, and one stage waits on another. This lab closes that gap on the cheapest possible instance of the file: no Azure subscription, no billable resource, nothing but a free Azure DevOps organisation and a browser. You commit the same shape the class taught — a Build stage with an ordinary job, a Deploy stage with a deployment job — watch both go green, then remove the one line the class warned you about and watch the deploy fail for exactly the reason it predicted.

Read it once. Break it once. Then you own it.

Everything here happens in the browser, at dev.azure.com.

# in the browser, not a terminal
1. Sign in at https://dev.azure.com with your Microsoft account
2. "Create new organization" > pick a name and a region > Continue
3. "Create a new project" named  campux-warehouse
   - Visibility: Private
   - Version control: Git
   - Work item process: Basic

Use the Repos web editor — Repos → Files → New → File — to add two files at the repository root. The first is a placeholder "build," so npm ci and npm run build have something real to do without needing an actual application:

# package.json — at the repo root
{
  "name": "campux-warehouse",
  "version": "1.0.0",
  "scripts": {
    "build": "echo 'warehouse build complete' > dist-marker.txt"
  }
}

The second is the pipeline itself — same shape as the class: a CI trigger, a PR trigger, a Build stage whose ordinary job gets its checkout implicitly, and a Deploy stage whose deployment job does not — so it checks out source explicitly on purpose, then reads a file from that source to prove the checkout mattered:

# azure-pipelines.yml — committed at the repository root
trigger:
  branches:
    include: [ main ]

pr:
  branches:
    include: [ main ]

stages:
  - stage: Build
    jobs:
      - job: build
        pool:
          vmImage: ubuntu-latest
        steps:
          # checkout: self is implicit here — source is already present
          - script: |
              npm ci --no-audit --no-fund || true
              npm run build
            displayName: Install and build

  - stage: Deploy
    dependsOn: Build
    jobs:
      - deployment: deployWarehouse
        pool:
          vmImage: ubuntu-latest
        environment: warehouse-production
        strategy:
          runOnce:
            deploy:
              steps:
                - checkout: self          # deployment jobs do NOT auto-checkout — this is the line we break
                - script: |
                    echo "Deploying the warehouse build..."
                    cat README.md
                  displayName: Deploy build to the warehouse app

Point Azure Pipelines at the file you just committed, then watch both stages go green.

# in the browser
1. Pipelines > Create Pipeline
2. "Where is your code?" > Azure Repos Git
3. Select the  campux-warehouse  repository
4. "Configure your pipeline" > Existing Azure Pipelines YAML file
5. Branch: main   Path: /azure-pipelines.yml
6. Review, then "Run"

The first run against a fresh environment name usually pauses once, asking you to approve the deployment job's use of warehouse-production — approve it. That approval creates the environment; every later run against the same name skips it.

Now do on purpose what people do by accident. Open azure-pipelines.yml in the Repos web editor, delete the - checkout: self line from the Deploy stage's steps, and commit straight to main. The CI trigger fires the pipeline again automatically.

Put the line back exactly where it was, first step of the deploy hook, and commit again.

strategy:
  runOnce:
    deploy:
      steps:
        - checkout: self          # restored
        - script: |
            echo "Deploying the warehouse build..."
            cat README.md
          displayName: Deploy build to the warehouse app

Nothing here billed you — an idle Azure DevOps organisation, project, and pipeline cost nothing while they sit unused. Tear down anyway; a stray pipeline nobody remembers is exactly the debris a real project accumulates.

# in the browser
1. Pipelines > select the pipeline > ⋯ > Delete
2. Pipelines > Environments > warehouse-production > ⋯ > Delete environment
3. Optional — remove the whole project:
   Organization settings > Projects > campux-warehouse > ⋯ > Delete
4. Optional — remove the whole organisation if you made it just for this lab:
   Organization settings > Overview > Delete

You created an Azure DevOps organisation and project from nothing, committed a two-stage azure-pipelines.yml, watched a build job and a deployment job run on separate agents, and proved with your own broken and fixed run — not a paragraph you took on faith — that a deployment job does not check out source automatically. You know what a CI trigger and a PR trigger each answer, why stages hold jobs and jobs hold steps, and the one line that catches almost everyone moving from GitHub Actions. The credential this pipeline is missing on purpose — a real, secret-free connection to Azure, scoped to one resource group — is the next lab.