Cloud Architecture

The cloud is not a bigger data center; it is a set of failure domains with prices attached. Every region, zone, and managed service is a boundary that fails independently and bills differently. Architecture in the cloud is mostly the discipline of choosing which boundaries your system can survive crossing, and which ones you pay to avoid.

Most bad cloud architectures are not wrong on features — they are wrong on failure domains, built as if a region or a disk is permanent. Design for the boundary to fail, then decide what you're willing to pay to make that survivable.

1. Put failure domains on paper before compute

Draw the regions, zones, and managed-service boundaries before you draw a single instance or container. Every one of those lines is a place where a real outage has happened to someone. A single-AZ deployment is a bet that AZ never fails; a single-region deployment is a bet the region never does. Neither bet needs to be wrong — but it must be a decision, not a default.