As the pace and complexity of application development and delivery have increased, the role of DNS has changed considerably. Originally, DNS was a simple on-premises location service for matching IP addresses to correct hostnames. As applications have moved from local data centers to the public cloud, the role of DNS has expanded to the current role of a sophisticated director, controlling global and site load balancing, traffic steering, and providing intelligent response to user requests.
Modern hybrid applications typically utilize public cloud components, including content delivery networks and cloud storage. All of these components need to communicate seamlessly despite any connectivity issues—meaning resiliency is critical. Historically, applications were developed in a self-contained localized data center, making connectivity issues smaller in scale and therefore easier to solve.
Read more at O’Reilly