Fault-Tolerant Infrastructure: From Knee-Jerk Solutions to More Expensive Ones

How to make the system fault-tolerant without Google's budget? We will analyze solutions for each level of architecture from DNS to database in three variants: minimal, optimal and industrial. I will show you, using examples of on-premise and Russian clouds like Yandex, VK, Selectel, what mistakes to avoid and how to save money without losing reliability.