Exams / DVA-C02 / Deployment strategies and rollbacks / Question 2
DVA-C02 practice question: Deployment strategies and rollbacks (2 of 2)
Deployment A free question from our original DVA-C02 practice exam. Try it, then open the answer to see why each option is right or wrong.
An application runs in an AWS Elastic Beanstalk environment. The team wants deployments that keep full capacity throughout and leave the existing instances untouched, so that a failed deployment is handled by terminating only the newly launched instances. Which deployment policy should they choose?
Choose one answer.
- AA. All at once
- BB. Rolling
- CC. Immutable
- DD. Rolling with additional batch
Show the answer and explanation
Answer: C
- A. Wrong: Every instance is updated at the same moment, so capacity briefly drops to zero and a failure affects the whole environment.
- B. Wrong: Batches of existing instances are taken out of service and updated, so capacity drops and old instances are changed.
- C. Right: Correct. A full set of new instances is launched in a separate Auto Scaling group alongside the old ones, which stay untouched until the new ones pass health checks.
- D. Wrong: Capacity is kept by adding a batch, but the existing instances are still updated in place batch by batch.
Explanation
Elastic Beanstalk deployment policies trade speed against safety. Immutable deployments launch new instances in a temporary Auto Scaling group, so if they fail health checks they are simply terminated and the original instances keep serving. Rolling policies update existing instances in place.
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