Abstract: A mechanism for controlling capacity in a multi-tenant Platform-as-a-Service (PaaS) environment in a cloud computing system is disclosed. A method includes detecting, by a resource control module, an occurrence of a trigger event for capacity analysis of virtual machines (VMs) in a multi-tenant PaaS system, obtaining an active capacity metric of each of the VMs, the active capacity metric comprising a result of dividing a number of containers that are currently executing in the VM by a maximum number of active containers allowed to execute in the VM, comparing the active capacity metric of each VM to an active capacity threshold of each VM, when the active capacity metric exceeds the active capacity threshold in all of the VMs in a district of the multi-tenant PaaS system and when a maximum actual capacity of containers in the district is not exceeded, adding a new VM to the district.