Your company has decided to make a major revision of their API in order to create better experiences for their developers. They need to keep the old version of the API available and deployable, while allowing new customers and testers to try out the new API. They want to keep the same SSL and DNS records in place to serve both APIs. What should they do?
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Correct Answer: D. Use separate backend pools for each API path behind the load balancer
Using separate backend pools for each API version behind a single load balancer is the correct approach. Google Cloud HTTP(S) Load Balancer supports URL map rules that route traffic to different backend services based on the request path (e.g., /v1/* → backend-v1, /v2/* → backend-v2). This keeps the same SSL certificate and DNS records intact, satisfying that requirement. Option A is wrong because adding a new load balancer would require new DNS/SSL configuration. Option B forces old clients to change, which contradicts keeping the old API available transparently. Option C adds unnecessary complexity and coupling between API versions — the old API shouldn't need to know about the new one. Option D cleanly separates concerns at the infrastructure level without touching application code.