1. A method comprising: selecting a subset of settings corresponding to values extracted from a plurality of virtual machine images, the plurality of virtual machine images comprising respective file systems comprised of files storing therein the values of the settings, the values of the setting controlling software in the virtual machine images, respectively; selecting a target one of the plurality of virtual machine images and obtaining target values of the settings from the target virtual machine image, the target values having been obtained by parsing files of the file system of the target virtual machine image to identify the settings and to extract the target values from the files, the settings occurring among each of the plurality of virtual machine images; accessing, in response to obtaining the target values, sample values of the settings, the sample values having been obtained from the plurality of virtual machine images by parsing through the files of the file systems of the plurality of virtual machine images to identify the settings and to extract the sample values of the settings; and forming, in response to obtaining the sample values of the settings, the subset by identifying similarities and differences of the target and sample values between the plurality of virtual machine images based on a statistic function.