Learn about large-scale service mesh migration challenges and solutions through PagerDuty's real-world experience in this conference talk from SREcon25 Europe/Middle East/Africa. Discover how a lean engineering team successfully migrated approximately 500 individual services to a service mesh architecture, achieving 95% completion within a year using the "away team" model where the core team made initial code changes and collaborated with other teams for reviews. Explore practical strategies for managing monotonous migration tasks without team burnout, understand the benefits and challenges of service mesh implementation including traffic management, flow control, multi-cluster load balancing, and mTLS, and gain insights into what makes a large-scale infrastructure migration successful when working with limited resources and existing legacy systems.