1. A computer-implemented method comprising: establishing, by a centralized server, a secured connection with an external server to obtain metadata of an operating system and information on provisioning computing resources, the centralized server being within an internal network of a customer; terminating, by the centralized server, the secured connection with the external server after obtaining the metadata and the information; generating, by the centralized server, a graphical user interface (GUI) to allow a user to manage a plurality of virtual machines running on a set of at least one physical machine coupled to the centralized server within the internal network while the centralized server remains disconnected from the external server, the plurality of virtual machines comprising at least one virtual host and at least one virtual guest; managing, by the centralized server, software packages of each of the plurality of virtual machines by keeping track of one or more applications installed on the plurality of virtual machines and versions of the one or more applications, scheduling updates of the one or more applications based on input from the user via the GUI, and scheduling installations of new applications for the software packages based on input from the user via the GUI; monitoring, by the centralized server, usage of one or more computing resources by the plurality of virtual machines, wherein the one or more computing resources include at least one of memory, CPUs, and computing threads provided by CPUs; and adjusting, by the centralized server, assignment of the one or more computing resources to the plurality of virtual machines based on the monitored usage of the one or more computing resources and input received from the user via the GUI.