Scaling hundreds of thousands of database clusters on Kubernetes requires careful consideration of statefulness, replication, node failures, backups, storage management, and mitigating failures. PlanetScale utilizes Kubernetes and Vitess to manage its databases, leveraging the Vitess Operator to streamline complex management tasks. By utilizing cloud storage and persistent volume claims, PlanetScale can dynamically allocate storage as needed, ensuring optimal performance and availability. Additionally, the use of Vitess tablets for backups allows for efficient data replication and validation, while the Vitess Operator automatically handles pod failures and provision new resources to maintain database uptime.