Methods, systems, and computer programs for creating isolated environments that include virtual machines (VM) and networks in a virtual infrastructure are presented. The method includes an operation to define a configuration of a virtual system which includes VMs, virtual network interface cards (VNIC) in the VMs, and configuration local networks (CLN). Further, the method associates each VNIC with one of the CLNs and transmits instructions to the virtual infrastructure for deploying the configuration. Deploying the configuration includes instantiating VMs and CLNs in the virtual infrastructure. Each VM is instantiated in a host monitored by a virtual lab server, and the CLNs are instantiated in the same hosts where the VMs have been instantiated. Only VMs from the configuration can connect to the instantiated CLNs. The method further transmits instructions to the virtual infrastructure to customize the VMs by executing the customization instructions in the guest operating systems of the VMs to configure the VMs' VNICs.