AZ-305 Practice Question 8: Global HTTP Load Balancing
Microsoft Azure Solutions Architect Expert (AZ-305) · Test 1 · question 8 of 10
A media company serves an HTTPS web application from identical deployments in West Europe, East US, and Southeast Asia. Users report slow page loads from whichever region is farthest away, and a recent regional incident took several minutes to route around because clients kept resolving the failed region's address. The redesign must:
- send each user to the healthy deployment with the lowest latency, - shift traffic away from an unhealthy region within seconds of a failed health probe, - enforce one managed web application firewall policy for all three regions, - cache static assets at the network edge and terminate TLS there.
Which service should the design put in front of the three deployments?
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Answer:
Front Door is Azure's global, Layer-7 application delivery network. It is the only option here that covers the whole requirement list at once: it routes each request from the point of presence nearest the user to the lowest-latency healthy backend, it proxies the traffic itself so an unhealthy backend is removed within seconds of a failed probe, it attaches a WAF policy at the edge in front of every backend, and it provides TLS offload and CDN caching for static content.
Option B fails three of the four requirements. Traffic Manager balances at the DNS level: it hands the client an address and steps out of the data path, so it offers no WAF, no TLS termination and no caching. Its failover is also gated by DNS TTL and by clients and resolvers that cache records past it, the exact "clients kept resolving the failed region" symptom the redesign is meant to fix.
Option C puts a regional service in a global role. Application Gateway is a regional load balancer; placing one in West Europe forces users in Asia and North America to hairpin their traffic through Europe, worsening the latency complaint, and it makes West Europe a single point of failure for all three deployments.
Option D operates at the wrong layer. Cross-region Load Balancer is a Layer-4 service for TCP and UDP. It has no notion of HTTP, so it cannot offer WAF inspection, TLS offload, path-based routing, or edge caching.
Reference: Load-balancing options - Azure Architecture Center