Based on this Link, auto scaling instances or partitions are provided from service fabric.
However, what's confusing is if this can also provide auto-scaling in/out of the nodes(VMs / actual physical environment), which seems not mentioned explicitly.
Yes, you can auto scale the cluster as well, assuming that you are running in Azure. This will be done based on performance counter data. It works by defining rules on the VM scaleset.
Note that in order to automatically scale down gracefully, it's recommended you use the durability level Gold or Silver, otherwise you'll be responsible to drain the node before it's taken out of the cluster.