dotnet-ado-unique

What this skill does

# dotnet-ado-unique

Azure DevOps-exclusive features not available in GitHub Actions: Environments with approvals and gates (pre-deployment checks, business hours restrictions), deployment groups vs environments (when to use each), service connections (Azure Resource Manager, Docker Registry, NuGet), classic release pipelines (legacy migration guidance to YAML), variable groups and library (linked to Azure Key Vault), pipeline decorators for organization-wide policy, and Azure Artifacts universal packages.

**Version assumptions:** Azure DevOps Services (cloud). YAML pipelines with multi-stage support. Classic release pipelines for legacy migration context only.

**Scope boundary:** This skill owns ADO-exclusive platform features that have no direct GitHub Actions equivalent. Composable YAML pipeline patterns (templates, triggers, multi-stage) are in [skill:dotnet-ado-patterns]. Build/test pipeline configuration is in [skill:dotnet-ado-build-test]. Publishing pipelines are in [skill:dotnet-ado-publish]. Starter CI templates are owned by [skill:dotnet-add-ci].

**Out of scope:** Composable pipeline patterns (templates, triggers) -- see [skill:dotnet-ado-patterns]. Build/test pipeline configuration -- see [skill:dotnet-ado-build-test]. Publishing pipelines -- see [skill:dotnet-ado-publish]. Starter CI templates -- see [skill:dotnet-add-ci]. GitHub Actions equivalents -- see [skill:dotnet-gha-patterns], [skill:dotnet-gha-build-test], [skill:dotnet-gha-publish], [skill:dotnet-gha-deploy]. CLI release pipelines -- see [skill:dotnet-cli-release-pipeline].

Cross-references: [skill:dotnet-add-ci] for starter CI templates, [skill:dotnet-cli-release-pipeline] for CLI-specific release automation.

---

## Environments with Approvals and Gates

### Defining Environments in YAML

Environments are first-class Azure DevOps resources that provide deployment targeting, approval gates, and deployment history:

```yaml
stages:
  - stage: DeployStaging
    jobs:
      - deployment: DeployToStaging
        pool:
          vmImage: 'ubuntu-latest'
        environment: 'staging'
        strategy:
          runOnce:
            deploy:
              steps:
                - download: current
                  artifact: app
                - script: echo "Deploying to staging"

  - stage: DeployProduction
    dependsOn: DeployStaging
    jobs:
      - deployment: DeployToProduction
        pool:
          vmImage: 'ubuntu-latest'
        environment: 'production'
        strategy:
          runOnce:
            deploy:
              steps:
                - download: current
                  artifact: app
                - script: echo "Deploying to production"
```

Environments are created automatically on first reference. Configure approvals and gates in Azure DevOps > Pipelines > Environments > (select environment) > Approvals and checks.

### Approval Checks

| Check Type | Purpose | Configuration |
|-----------|---------|---------------|
| Approvals | Manual sign-off before deployment | Assign approver users/groups |
| Branch control | Restrict deployments to specific branches | Allow only `main`, `release/*` |
| Business hours | Deploy only during allowed time windows | Define hours and timezone |
| Template validation | Require pipeline to extend a specific template | Specify required template path |
| Invoke Azure Function | Custom validation via Azure Function | Provide function URL and key |
| Invoke REST API | Custom validation via HTTP endpoint | Provide URL and success criteria |
| Required template | Enforce pipeline structure | Specify required extends template |

### Configuring Approval Checks

Approval checks are configured in the Azure DevOps UI, not in YAML. The YAML pipeline references the environment, and the checks are applied:

```yaml
# Pipeline YAML -- environment reference triggers checks
- deployment: DeployToProduction
  environment: 'production'  # checks configured in UI
  strategy:
    runOnce:
      deploy:
        steps:
          - script: echo "This runs only after all checks pass"
```

**Approval configuration (UI):**
- Navigate to Pipelines > Environments > production > Approvals and checks
- Add "Approvals" check: assign individuals or groups
- Set minimum number of approvers (e.g., 2 for production)
- Enable "allow approvers to approve their own runs" only if appropriate

### Business Hours Gate

Restrict deployments to specific time windows to reduce risk:

- Navigate to Pipelines > Environments > production > Approvals and checks
- Add "Business Hours" check
- Configure: Monday-Friday, 09:00-17:00 (team timezone)
- Pipelines will queue and wait until the window opens

### Pre-Deployment Validation with Azure Functions

```yaml
# The environment's "Invoke Azure Function" check calls:
# https://myvalidation.azurewebsites.net/api/pre-deploy
# with the pipeline context as payload.
# Returns 200 to approve, non-200 to reject.

- deployment: DeployToProduction
  environment: 'production'  # Azure Function check configured in UI
  strategy:
    runOnce:
      preDeploy:
        steps:
          - script: echo "Pre-deploy hook (in-pipeline)"
      deploy:
        steps:
          - script: echo "Deploying"
      routeTraffic:
        steps:
          - script: echo "Routing traffic"
      postRouteTraffic:
        steps:
          - script: echo "Post-route validation"
```

The `preDeploy`, `routeTraffic`, and `postRouteTraffic` lifecycle hooks execute within the pipeline. Environment checks (approvals, Azure Function gates) execute before the deployment job starts.

---

## Deployment Groups vs Environments

### When to Use Each

| Feature | Deployment Groups | Environments |
|---------|------------------|--------------|
| Target | Physical/virtual machines with agents | Any target (VMs, Kubernetes, cloud services) |
| Agent model | Self-hosted agents on target machines | Pool agents or target-specific resources |
| Pipeline type | Classic release pipelines (legacy) | YAML multi-stage pipelines (modern) |
| Approvals | Per-stage in classic UI | Checks and approvals on environment |
| Rolling deployment | Built-in rolling strategy | `strategy: rolling` in YAML |
| Recommendation | Legacy workloads only | All new projects |

### Deployment Group Example (Legacy)

Deployment groups install an agent on each target machine. Use only for existing on-premises deployments:

```yaml
# Classic release pipeline (not YAML) -- for reference only
# Deployment groups are configured in Project Settings > Deployment Groups
# Each target server runs the ADO agent registered to the group
```

### Environment with Kubernetes Resource

```yaml
- deployment: DeployToK8s
  environment: 'production.my-k8s-namespace'
  strategy:
    runOnce:
      deploy:
        steps:
          - task: KubernetesManifest@1
            inputs:
              action: 'deploy'
              manifests: 'k8s/*.yml'
              containers: '$(ACR_LOGIN_SERVER)/myapp:$(Build.BuildId)'
```

Environments can target Kubernetes clusters and namespaces. Register the cluster as a resource under the environment in the Azure DevOps UI.

### Migration from Deployment Groups to Environments

1. Create environments matching existing deployment group names
2. Configure the same approval gates in the environment's Approvals and checks
3. Convert classic release pipeline stages to YAML `deployment` jobs targeting the new environments
4. Use `strategy: rolling` for incremental deployments equivalent to deployment group behavior

---

## Service Connections

### Azure Resource Manager (ARM)

Service connections provide authenticated access to external services. ARM connections enable Azure resource deployments:

```yaml
- task: AzureWebApp@1
  displayName: 'Deploy to Azure App Service'
  inputs:
    azureSubscription: 'MyAzureServiceConnection'
    appType: 'webAppLinux'
    appName: 'myapp-staging'
    package: '$(Pipeline.Workspace)/app'
```

**Creating an ARM service connection:**
- Navigate t