Microservice API Gateways GCSA Practice Questions (Page 5)

Questions 21–25

1. 21foundation · easy

   Which API gateway function is used to control the number of requests a client can make within a given time period?

   • ARequest routing
   • BRate limiting
   • CResponse transformation
   • DService discovery
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2. 22expert · hard

   A startup has a small team and a single microservice. They expect rapid growth and plan to add many services. They want to minimize initial operational overhead but also avoid a major re-architecture later. Which API gateway deployment pattern is most appropriate?

   • AExpose the service directly to clients and add a gateway only when absolutely necessary.
   • BUse a sidecar proxy on the single service and plan to add more sidecars later.
   • CDeploy per-service gateways from the start, even though there is only one service.
   • DStart with a centralized gateway and adopt per-service or sidecar gateways only when the team and service count grow.
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4. 23expert · hard

   A team is performing a blue/green deployment of a microservice. They want to test the green version with a subset of users before switching all traffic. They also need to ensure that if the green version fails, they can quickly revert. Which gateway configuration supports this?

   • AUse header-based routing to send requests from internal testers to the green version, while all other traffic goes to blue.
   • BUse weighted routing to send 50% of traffic to green and 50% to blue.
   • CCreate a separate gateway for the green version and have testers use a different URL.
   • DUpdate the gateway to route all traffic to green immediately and monitor for errors.
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5. 24application · medium

   A company is rolling out a microservices-based e-commerce platform. The API gateway must authenticate requests using OAuth2 tokens, route requests to the appropriate backend services, and enforce per-client rate limits. The team wants to minimize the amount of custom code and prefers to use built-in gateway features. Which configuration should the team implement?

   • ADisable authentication at the gateway and rely on each backend service to validate tokens, while using a load balancer to distribute traffic and a separate rate-limiting service.
   • BConfigure the gateway to validate JWT signatures against the authorization server's public keys, define routes based on URL paths, and set rate-limit policies per client ID.
   • CImplement a custom authentication filter in the gateway that calls the authorization server on every request, then route based on the token's claims, and apply a global rate limit to all clients.
   • DUse the gateway only for TLS termination and static routing, and implement authentication and rate limiting in a shared library used by all microservices.
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6. 25expert · hard

   A team is deploying a new version of a microservice that changes the request schema. They want to avoid breaking existing clients while gradually migrating them. The API gateway supports both versioned routes and request/response transformation. Which strategy minimizes client disruption?

   • AUse rate limiting to slowly allow clients to use the new version.
   • BImmediately update the existing route to the new version and require all clients to adapt at once.
   • CKeep the old route for legacy clients and create a new route for the new version, using transformation to bridge the old and new schemas during migration.
   • DDisable the old route and rely on clients to discover the new schema via documentation.
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