For a highly available web application using stateless web servers, the suitable services are SLB (Server Load Balancer), ECS (Elastic Compute Service), and OSS (Object Storage Service). The SLB helps distribute incoming traffic across multiple ECS instances, ensuring high availability and fault tolerance. ECS provides scalable compute resources for the web servers. OSS is useful for storing static files and content that the web servers might need to serve, which is essential for a stateless architecture. RDS and MaxCompute are not directly related to the requirements of making a web server stateless or ensuring its high availability.