In the complex and unpredictable environment of the internet, Fastly, a global Content Delivery Network (CDN), focuses on resilience by emphasizing quick response and recovery from disruptions rather than attempting to prevent all failures. Two key pillars of their resilient strategy are fault isolation and graceful degradation. Fault isolation involves designing the CDN to limit the impact of disruptions, such as power failures or DDoS attacks, by restricting the fault's effect to a minimal area, allowing other services to continue unaffected. This is achieved through software engineering principles, including modular design, redundancy, and robust error checking. Meanwhile, graceful degradation ensures systems continue operating in a reduced capacity rather than failing completely, thereby maintaining some level of service during disruptions. Techniques like shedding non-critical load and serving stale content help sustain user experience and provide operational staff with the opportunity to diagnose and address issues without immediate pressure to restore full functionality. These strategies, supported by strong observability, enable Fastly to build a disruption-resistant infrastructure that can withstand and recover from challenges efficiently.