• VID shall allow the Operations user to choose a Scale-Out workflow. (NEW)
• VID will allow the user to select the Subscriber_>service type-> NF_Role-> Source_VF_Model_Version _>list of VNFs that needs to be scaled out i.e add VF Module(s) that may have one or more VMs in it (NEW).
• Should VID allow the user to scale out multiple VF_modules within the same VNF.
• VID will allow the user to add the quantity of VF-Modules to be scaled out for the given VNF . (NEW)
• Upon selecting the NF-Role, VID will query A&AI, Get-Generic-VNF, to retrieve the "In-Service" View of all the VNFs with a prov-status =PROV.
• For the NF_Role selected, VID will present a list to the user of VNFs with a prov-status=PROV.
• VID will present a In Service View that shows the VF_Module and the VM(s) within each VF-Module associated with the VNF
• VID will check AAI to determine how many VF Module instances are In-Service and compare that to the Max Instance property, max_vf_module_instances, to determine whether the VF-Module should be allowed.
• VID will specify the region, NF-Role, Number of VF-Modules to be added, homing, capacity and license placement information in the request to MO
• VID will  to invoke an API to Pause the Scale Out WF (New)
• VID will allow the user to Cancel the Scale Out WF if the Scale Out run time execution has not started. (NEW)

Source:

https://wiki.onap.org/display/DW/Scaling+Impacts+to+ONAP+Projects