Examples include maintaining a virtual pool of containers; receiving a request from a client for one of a plurality of services to performed; when the request includes client code, determining whether the request belongs to regular or priority queue based on two models; adding the request to an appropriate shard in the queue; getting the request from the selected one of the plurality of queues and assigning a container for the request from the virtual pool of containers, the client code to be executed in the container; and after the client code is executed in the container, deleting the container from the virtual pool.