I am trying to deploy JSS-React app in Service Fabric cluster, does anyone know if - Sitecore-JSS application supported in Service Fabric? - Can I create .net Core application for this?
The question is pretty vague so there are several possible answers.
First note that the Sitecore setup (CM, CD, etc) backing any JSS application can certainly not run on service fabric.
If you want to use .NET Core, then it is theoretically possible to consume JSS's services (i.e. layout service) over HTTP from .NET Core, then render the app using ASP.NET Core MVC instead of JS. This is probably not what you mean, however - hosting a JSS JS app within a .NET Core environment would basically mean using .NET Core to shell out to Node, which is pretty much a waste.