Exams / DVA-C02 / Versions, aliases and stages / Question 1
DVA-C02 practice question: Versions, aliases and stages (1 of 3)
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.
Clients call a Lambda function through an alias named live, which points to version 7. The developer has published version 8 and wants 10% of invocations through live to go to version 8 while the rest stay on version 7, without changing any clients. What should the developer do?
Choose one answer.
- AA. Point the live alias at $LATEST and update $LATEST with the new code.
- BB. Create a second alias for version 8 and have clients pick an alias at random.
- CC. Configure provisioned concurrency of 10% on version 8.
- DD. Configure weighted routing on the live alias, sending 10% to version 8.
Show the answer and explanation
Answer: D
- A. Wrong: Every invocation would get the new code at once, and a weighted alias cannot point to $LATEST.
- B. Wrong: This requires client changes, which the developer wants to avoid.
- C. Wrong: Provisioned concurrency keeps environments initialised. It does not route traffic between versions.
- D. Right: Correct. A weighted alias splits invocations between two published versions behind one name.
Explanation
A Lambda alias can point to two published versions and split traffic between them by weight. This enables canary-style releases without client changes. Both versions must be published (not $LATEST) and must use the same execution role and dead-letter queue configuration.
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