DNS fallback for better resilience

Algolia is working towards a highly available architecture with a focus on ensuring that every component can fail safely without affecting the service. The company uses NSONE for its data-driven DNS, which provides control over traffic routing to servers. However, they also use AWS Route53 as a secondary DNS provider due to its performance and API integration capabilities. Algolia's latest API clients support multiple domain names, with "algolia.net" served by NSONE for speed and intelligence, and "algolianet.com" served by Route53 as a backup in case of failure. This approach aims to provide better reliability and peace of mind for customers and the company itself.