1. A computer-implemented method, comprising: detecting, by a resource control module executing on a computing device, an occurrence of a trigger event for capacity analysis of virtual machines (VMs) in a multi-tenant Platform-as-a-Service system; obtaining, by the resource control module, 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, by the resource control module, the active capacity metric of each VM to an active capacity threshold associated with the 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.