IT assets of the IT system are grouped into asset groups by verifying characteristics and relations of the IT assets against affinity criteria in decreasing order of an affinity level of corresponding affinity criteria. A description of target platforms eligible to host the IT assets includes an indication of one or more hosting constraints and an indication of a complexity level of each target platform. At least part of the IT assets of the asset groups are mapped onto respective the target platforms by verifying the characteristics and/or relations of the IT assets of the asset groups, in decreasing order of the affinity level of the corresponding affinity criteria. The IT system is configured by hosting each mapped IT asset on the respective one or more target platform, which aggregates IT assets that have a higher affinity level on target platforms that have a lower complexity level.