AZ-400 Practice Test 2 — 25 Questions

Question 1

Which THREE components are required to set up a self-hosted agent pool in Azure Pipelines?

Accepted Answer

The agent software installed on the target machine. The self-hosted agent requires the Azure Pipelines agent software to be installed on the target machine. This software, which includes the agent listener and worker processes, is what registers the machine with the agent pool and executes pipeline jobs. Without the agent software, the machine cannot communicate with Azure Pipelines or run any tasks.

Answer

A deployment group target

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Azure VM extension for Azure Pipelines Agent

Question 2

Your team uses Azure Repos for source control. You need to enforce that all builds must pass unit tests before code can be merged into the main branch. Which branch policy should you configure?

Accepted Answer

Add a build validation policy that triggers the CI pipeline and requires it to succeed.. Azure Repos branch policies allow you to add a build validation policy that triggers a CI pipeline (e.g., a YAML or classic build pipeline) and requires it to succeed before a pull request can be completed. This ensures that all code merged into the main branch has passed unit tests, enforcing quality gates directly in the PR workflow.

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Require a linked work item.

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Require a minimum number of reviewers.

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Require comment resolution.

Question 3

Your release pipeline deploys a web app to Azure App Service. You need to implement safe deployment practices that minimize downtime and enable quick rollback. Which THREE strategies should you recommend?

Accepted Answer

Deploy to a staging slot first, validate, then swap.. Deploying to a staging slot first allows you to validate the application in a production-like environment without affecting live traffic. Once validated, swapping the staging and production slots ensures zero-downtime deployment by instantly routing all traffic to the validated version. This is a core safe deployment practice for Azure App Service.

Answer

Use rolling deployment with manual step to approve each instance.

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Deploy directly to the production slot.

Question 4

Which TWO approaches can you use to enforce consistent commit message conventions across your GitHub repositories?

Accepted Answer

Use a GitHub Action to validate commit messages on push. GitHub Actions can be configured with a workflow that triggers on `push` events to validate commit messages against a regex pattern, rejecting non-conforming commits. Option D is correct because repository rulesets (or branch protection rules) allow you to define required commit message patterns that must match before a push is accepted, enforced server-side. Both approaches enforce conventions consistently across all contributors.

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Add a .gitattributes file

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Set the default branch to main

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Set up an issue template

Question 5

You need to implement a build retention policy that automatically deletes old builds after 30 days, but keeps the latest 5 builds regardless of age. Which configuration should you use?

Accepted Answer

Set 'Days to keep builds' to 30 and 'Minimum number of builds to keep' to 5. In Azure Pipelines, the 'Days to keep builds' and 'Minimum number of builds to keep' settings work together to enforce a retention policy that deletes builds older than 30 days while ensuring that at least the latest 5 builds are retained, even if they exceed the age limit. This configuration directly matches the requirement to delete old builds after 30 days but keep the latest 5 builds regardless of age.

Answer

Set 'Number of days to keep runs' to 30 and 'Number of runs to keep' to 5

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Set 'Maximum retention policy' to 30 days and 'Number of builds to retain' to 5

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Set 'Number of days to keep artifacts' to 30 and 'Number of artifacts to keep' to 5

Question 6

Refer to the exhibit. A build pipeline uses this trigger configuration. A developer pushes a commit to the 'main' branch that modifies files in '/src/app/' and '/src/tests/'. How many builds will be triggered?

Accepted Answer

1 build, because batchChanges is true.. The trigger configuration has `batchChanges` set to `true`. When `batchChanges` is enabled, Azure Pipelines groups all commits that arrive while a build is in progress into a single build, rather than triggering a separate build for each commit. In this scenario, the developer pushes a single commit that modifies files in both `/src/app/` and `/src/tests/`. Since `batchChanges` is true, only one build is triggered for that commit, regardless of the number of modified folders.

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0 builds, because the excluded path takes precedence.

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3 builds, because maxConcurrentBuildsPerBranch is 1 but batchChanges overrides.

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2 builds, one for each modified folder.

Question 7

A company uses Azure Pipelines to build a .NET Core application. The build takes 45 minutes due to dependency restoration. They want to reduce build time. What is the most effective strategy?

Accepted Answer

Cache the NuGet packages and enable caching in the pipeline. Caching NuGet packages in Azure Pipelines is the most effective strategy because dependency restoration is the primary bottleneck, often downloading hundreds of packages from nuget.org. By caching the ~/.nuget/packages folder, subsequent builds skip the network download entirely, reducing the 45-minute build time to minutes. This directly addresses the root cause—repetitive package restoration—without requiring additional infrastructure or parallelism.

Answer

Use parallel jobs in the pipeline

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Use a self-hosted agent with more CPU

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Enable incremental builds

Question 8

You are designing a release pipeline for a mission-critical application that must achieve zero-downtime deployments to Azure App Service (Web App for Containers). The application uses Azure SQL Database with schema migrations. The current deployment slot strategy uses staging and production slots. You need to ensure that during a swap, the staging slot is warmed up and the database schema is rolled back if the swap fails. Which combination of deployment slots and pre/post-swap actions should you implement?

Accepted Answer

Use three slots: production, staging, and a new slot for the new version. Apply schema changes in the new slot, then swap new to staging, warm up staging, then swap staging to production. On failure, swap staging back to production.. It uses three slots to isolate schema changes in a new slot, then swaps to staging for warm-up, and finally swaps to production. If the swap fails, rolling back staging to production reverses the schema changes, ensuring zero-downtime. This approach aligns with Azure App Service slot-swap best practices for mission-critical applications requiring database rollback capability.

Answer

Use two slots (staging and production) with auto-swap enabled. The auto-swap handles warm-up automatically. If the swap fails, Azure automatically rolls back.

Answer

Use three slots: production, staging, and a new slot for the new version. Apply schema changes in the new slot, then swap new slot to staging, then staging to production. On failure, swap staging back to production.

Answer

Use two slots (staging and production). Apply schema changes in staging before swap. If swap fails, manually redeploy the old version to production.

Question 9

Your organization uses Azure DevOps to manage CI/CD pipelines. The security team requires that all pipeline runs use a specific service connection that references a managed identity in Microsoft Entra ID. However, some developers have been using personal access tokens (PATs) in their pipelines, bypassing the managed identity. What should you implement to enforce the use of the managed identity service connection?

Accepted Answer

Use a pipeline decorator to validate the service connection and fail the pipeline if an unauthorized connection is used.. Pipeline decorators allow you to inject custom validation steps into every pipeline run at the organization or project level. By using a decorator that checks the service connection ID used in each job and fails the run if it does not match the approved managed identity connection, you can enforce compliance without relying on developer cooperation or manual policy configuration.

Answer

Configure a branch policy on the main branch to require a specific service connection.

Answer

Restrict the use of PATs by setting an agent pool-level permission.

Answer

Store the service connection ID in a variable group and reference it in each pipeline.

Question 10

Your Azure DevOps pipeline uses a YAML template to avoid duplication. The template defines common build steps. You need to override one of the steps in a specific pipeline without modifying the template. Which approach should you use?

Accepted Answer

Use template parameters with a 'steps' object that can be injected to override the step.. Azure DevOps YAML templates support parameterized steps objects. By defining a template parameter of type 'steps' with a default value, the calling pipeline can pass a custom steps object as an argument to that parameter, effectively overriding the default steps without modifying the template. No 'replace' keyword is used; the override is achieved by directly injecting the steps object via the parameter.

Answer

Use the 'overrides' keyword in the pipeline YAML to specify which steps to replace.

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Create a copy of the template and modify the step directly.

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Use a conditional 'if' statement in the template to skip steps based on a parameter.

Question 11

Refer to the exhibit. A release is created with the above command. The Dev environment starts deploying, but the Prod environment does not. Which is the most likely reason?

Accepted Answer

The Prod environment has a pre-deployment condition that waits for the Dev environment to succeed.. The exhibit shows a release pipeline with a sequential deployment strategy where the Prod environment has a pre-deployment condition configured to wait for the Dev environment to succeed. In Azure DevOps, pre-deployment conditions can be set to trigger only after a specific environment (like Dev) completes successfully. Since the Dev environment is still deploying, the Prod environment remains in a waiting state and does not start.

Answer

The Prod environment requires manual approval before deployment.

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The release definition ID 5 is incorrect.

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The build artifact with ID 123 is not accessible.

Question 12

The pipeline fails because the artifact is empty. What is the most likely cause?

Accepted Answer

The build output is not copied to the staging directory. The most common reason for an empty artifact in Azure Pipelines is that the build output files were not copied to the staging directory (typically $(Build.ArtifactStagingDirectory)) before the PublishBuildArtifacts task runs. The PublishBuildArtifacts task publishes whatever is in the staging directory; if no files are copied there, the artifact will be empty. This is a standard pattern where a Copy Files task or similar step must explicitly place the build outputs into the staging directory.

Answer

The projects pattern '**/*.csproj' does not match any files

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The task 'PublishBuildArtifacts@1' is misspelled

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The artifact name 'drop' is invalid

Question 13

Your company is a startup developing a mobile application with a small team of 5 developers. You use GitHub Free and want to implement a simple but effective branching strategy that supports continuous delivery. The team wants to release new features every week and be able to hotfix critical bugs quickly. They currently have a main branch and feature branches, but sometimes features are merged to main before they are fully tested, causing issues. You need to recommend a strategy that minimizes risk while keeping the process lightweight. The team does not want to use long-lived branches. What should you recommend?

Accepted Answer

Use GitHub Flow: developers create feature branches from main, open pull requests with required CI and at least one review, then merge to main. Hotfixes follow the same process.. GitHub Flow is the simplest and most effective strategy for a small team using GitHub Free that wants continuous delivery without long-lived branches. By requiring feature branches, pull requests with CI checks, and at least one review before merging to main, it ensures that all code is tested and reviewed before integration, preventing untested features from breaking main. Hotfixes follow the same lightweight process, allowing quick, safe patches without additional branch overhead.

Answer

Use a single main branch and create release branches for each weekly release; features are merged to release branches, then release branches are merged to main after testing.

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Allow developers to commit directly to main but require all commits to pass CI and be reviewed by at least one other developer after the fact.

Answer

Adopt GitFlow with develop and release branches.

Question 14

You are the DevOps lead for a financial services company. The company uses Azure DevOps Services with a single project containing multiple teams. The compliance team requires that all production deployments be approved by a change advisory board (CAB) member. Additionally, any deployment that changes a configuration value stored in Azure App Configuration must be audited. You have set up a release pipeline with a manual approval gate and a pre-deployment condition that runs a PowerShell script to validate configuration changes. However, the compliance team reports that some deployments bypassed the approval gate. Upon investigation, you find that developers with 'Edit release pipeline' permissions can modify the pipeline and remove the approval gate. You need to ensure that the approval gate cannot be bypassed by developers. You also need to ensure that any change to a configuration key is logged to Azure Monitor. What should you do?

Accepted Answer

Create a protected variable group that stores the approval gate configuration and set the pipeline to use it. Restrict edit permissions on the release pipeline to a security group that does not include developers. For configuration changes, use an Azure Resource Manager template with a deployment script that sends logs to Azure Monitor.. It addresses both requirements: restricting pipeline edit permissions to a security group that excludes developers prevents them from removing the approval gate, and using an ARM template with a deployment script that sends logs to Azure Monitor ensures configuration changes are audited. Protected variable groups secure sensitive configuration, but the key is permission separation and audit logging via ARM deployment scripts.

Answer

Create a new service connection with limited permissions and require that all pipeline runs use it. Use an Azure Policy to audit configuration changes.

Answer

Configure environment-level approvals in the release pipeline and use Azure Policy to enforce that all deployments go through the environment. Use diagnostic settings on App Configuration to stream logs to Azure Monitor.

Answer

Implement a branch policy on the release pipeline's YAML file in the repository to require approval for changes. Use a webhook to send configuration change events to Azure Monitor.

Question 15

Refer to the exhibit. The workflow runs successfully but the deployment fails because the Azure CLI is not authenticated. What should you add to the workflow to authenticate?

Accepted Answer

Add the 'azure/login' action with Azure credentials. The Azure CLI in the workflow requires authentication to interact with Azure resources. Adding the 'azure/login' action with valid Azure credentials (e.g., service principal secrets or OpenID Connect) establishes the necessary authentication context before any Azure CLI commands are executed, resolving the 'not authenticated' error.

Answer

Add the 'actions/setup-node' action

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Add the 'azure/webapps-deploy' action

Answer

Add the 'actions/github-script' action to use the GitHub token

Question 16

You are designing a communication strategy for your DevOps team. They use Microsoft Teams for collaboration. You need to automatically notify the team when a release to production fails. Which Azure DevOps integration should you use?

Accepted Answer

Configure a notification subscription in Azure DevOps to send a Teams webhook. Azure DevOps notification subscriptions can be configured to send alerts to a Teams channel via an incoming webhook. This allows automatic, real-time notifications to the DevOps team when a release to production fails, directly within their collaboration platform.

Answer

Set up an email subscription to the DevOps team

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Create a service hook to call a custom API

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Publish a Wiki page with deployment status

Question 17

Your team uses Git for source control. A developer accidentally committed a large binary file (500 MB) to the main branch. The push succeeded but other team members are now complaining about slow fetch times. What is the most efficient way to remove the file from the repository history?

Accepted Answer

Use 'git filter-repo' to remove the file from history. 'git filter-repo' is the recommended modern tool for permanently removing large files from Git history. It rewrites the repository's commit graph, eliminating the file from all commits, which reduces repository size and resolves slow fetch times for team members. Unlike BFG Repo-Cleaner, 'git filter-repo' is actively maintained and integrates natively with Git, making it the most efficient and reliable choice for this task.

Answer

Add the file to .gitignore and push again

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Use 'git revert' to undo the commit

Answer

Use BFG Repo-Cleaner

Question 18

You have a YAML pipeline that builds a Docker image and pushes it to Azure Container Registry (ACR). You need to dynamically set the image tag based on the build number. Which predefined variable should you use?

Accepted Answer

$(Build.BuildNumber). The `$(Build.BuildNumber)` variable represents the build number, which is the name of the completed build. It's often customized to include versioning information, and it's the appropriate variable to use when tagging Docker images based on the build number. `$(Build.BuildId)` is a unique numeric ID for the build record, but it is not the build number.

Answer

$(System.JobId)

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$(System.TeamProject)

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$(Build.BuildId)

Question 19

Your organization uses GitHub Actions and needs to enforce that all workflows pass required checks before a pull request can be merged. Which GitHub feature should you configure?

Accepted Answer

Branch protection rules with required status checks. Branch protection rules with required status checks enforce that all configured GitHub Actions workflows must pass before a pull request can be merged. This ensures that any workflow defined in the repository (e.g., CI, linting, security scans) produces a successful check run, and the merge is blocked if any required check fails or is pending.

Answer

Workflow triggers

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Required reviewers

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Environment protection rules

Question 20

Your team is using Git with Azure Repos. A developer accidentally committed a large binary file to the main branch. What is the recommended way to permanently remove it from the repository history?

Accepted Answer

Use 'git filter-branch' to remove the file from history. `git filter-branch` (or its modern replacement `git filter-repo`) rewrites the entire repository history to permanently remove a file from all commits. This is the recommended approach when a large binary file has been committed to the main branch and must be expunged from history to reduce repository size and prevent it from being cloned by others.

Answer

Delete the file and commit the deletion

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Ignore the file using .gitignore

Answer

Revert the commit using 'git revert'