AZ-400 Question 199
Single answerYou are responsible for an Azure DevOps pipeline that is triggered automatically whenever new code is pushed to the main branch. Recently, you have noticed that builds are frequently stuck in queue for extended periods, indicating that concurrent runs may be limited. You want to prevent long wait times by allowing more builds to run at once. Which action should you take to properly address this concurrency limit so multiple builds can run in parallel?
- A
Add a 'concurrency' field to the YAML pipeline and set it to '0' for unlimited concurrency.
- B
Purchase or assign additional parallel jobs in your Azure DevOps organization settings based on your licensing constraints.
- C
Disable scheduled triggers in your pipeline configuration to reduce queue volume.
- D
Include more agent pool references in your YAML file so that each build uses a different pool.
Show answer and explanation
Correct answer: B
Explanation
In Azure DevOps, concurrency (i.e., how many builds can run simultaneously) is limited by the number of parallel jobs your organization has. Even if you modify your pipeline YAML or add different agent pools, you still need enough parallel job licenses to run multiple builds at the same time. Refer to Microsoft� Azure DevOps documentation on 'Parallel jobs in Azure Pipelines' for details on assigning or purchasing additional parallel jobs (https://learn.microsoft.com/azure/devops/pipelines/licensing/concurrent-jobs).
- A. Incorrect.
Option 1: In Azure DevOps, the 'concurrency' keyword is not used in the same way it is in other systems (e.g., GitHub Actions). Simply adding a 'concurrency' field with '0' in your YAML won't override the organization-level or pipeline-level parallel job limits. This option reflects a common misconception from mixing up different CI/CD systems.
- B. Correct.
Option 2 (Correct): In Azure DevOps, the maximum number of parallel jobs is determined by your purchased/assigned license level (e.g., free tier, paid tier). To truly increase concurrent builds, you must either purchase additional parallel pipelines or assign more parallel jobs. This allows multiple builds to run in parallel instead of queueing.
- C. Incorrect.
Option 3: Disabling triggers might reduce how many runs get queued, but it does not directly increase concurrency. It only decreases how often your pipeline runs, which is not a suitable solution if you genuinely need all those builds to run more quickly and in parallel.
- D. Incorrect.
Option 4: Pointing to multiple agent pools in the YAML file does not guarantee that each build will run in parallel if your organization� parallel job limit is already reached. Without additional parallel capacity, extra pools for the same pipeline won�t help increase concurrency.