Section 6.8.1.8 of SOL001 v2.5.1 https://www.etsi.org/deliver/etsi_gs/NFV-SOL/001_099/001/02.05.01_60/gs_nfv-sol001v020501p.pdf requires the following:

    For a given VNFD, a new VNF node type shall be defined following the below requirements:
    a) The node type shall be derived from: tosca.nodes.nfv.VNF.
    b) All properties listed in tosca.nodes.nfv.VNF where the "required:" field is set to "true" shall be included with their values indicated as constraints and as default values.

    ......

This requires SDC to support user defined node types. Otherwise, a SOL001 compliant VNF csar can not be onboarded.