Embodiments are provided for enabling dynamic reallocation of resources in a multi-tenant distributed database. According to certain aspects, a management services module allocates multiple portions of computer resources for respective operation of multiple services by multiple customers. A quality of service (QoS) controller detects that one of the services is attempting to exceed its allocated portion of resources, and identifies an available portion of another allocated portion of resources. In response, the QoS controller causes the management services module to dynamically allocate the available portion to the detected service so that the detected service is able to operate without error or delay.