A method of installing an image of a virtualization software installing an image of a virtualization software in a heterogeneous duster of hosts that include first hosts having server hardware of a first type and at least one second host having server hardware of a second type, includes: in response to a user input, generating a software specification that specifies a base image of the virtualization software and an add-on image of the virtualization software; retrieving metadata of the base image and metadata of add-on image; generating first and second desired images of the virtualization software, which are to be applied respectively to the first hosts and the at least one second host, based on the metadata of the base image and metadata of the add-on image; and instructing each of the first and second hosts to install a desired image of the virtualization software therein.