Cloud architecture defines how applications and infrastructure are distributed across geographical locations, isolated zones, and interconnected networks to achieve availability, resilience, and performance goals. It operates at the physical layer (regions, availability zones, data centers) and the logical layer (failover strategies, redundancy patterns, replication models). Understanding cloud architecture is essential because a single misconfigured zone placement or missing health check can turn a minor hardware failure into a service-wide outage. The key mental model: cloud providers give you building blocks for resilience—but you must assemble them correctly.

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