Large scale applications are increasingly built by composing sets of microservices. In this model the functionality for a single application might be split across 100s or 1000s of microservices. Resource provisioning for these applications is complex, requiring administrators to understand both the functioning of each microservice, and dependencies between microservices in an application. In this paper we present ThrottleBot, a system that automates the process of determining what resource when allocated to which microservice is likely to have the greatest impact on application performance. We demonstrate the efficacy of our approach by applying ThrottleBot to both synthetic and real world applications. We believe that ThrottleBot when combined with existing microservice orchestrators, e.g., Kubernetes, enables push-button deployment of web scale applications.