Created attachment 1420039 [details]
notice nothing is under the private_subnet dropdown box.

looks to be a bug/limitation of horizon

From /usr/share/openstack-dashboard/openstack_dashboard/dashboards/project/stacks/forms.py
 
 
   def _populate_custom_choices(self, custom_type):
        if custom_type == 'neutron.network':
            return instance_utils.network_field_data(self.request, True)
        if custom_type == 'nova.keypair':
            return instance_utils.keypair_field_data(self.request, True)
        if custom_type == 'glance.image':
            return image_utils.image_field_data(self.request, True)
        if custom_type == 'nova.flavor':
            return instance_utils.flavor_field_data(self.request, True)
        return []

So it look like this was never implemented in Horizon.

Is it possible to type something manually in the field? If not I would call it a bug.

If it's just a case of the user having to do it manually when it could be populated automatically then this probably more of an RFE.

As a workaround, you can remove the subnet constraint from the parameter.

Looking at the horizon code, it looks like a bug, as there is no fallback when a constraint is not processed. This is opened against OSP10, so it would fall under horizon. Not sure how high the priority is though.

When I remove the constraint from the private_subnet parameter it does not give a dropdown for it in horizon. I'm not sure that's a workaround, it just hides the problem .

Well, it's a workaround for the bug "I can't create a stack with this constraint". It doesn't fix the missing feature "The subnet list is not populated". You didn't answer Zane's question too?

No, we can not type something manually into this field. It's an empty dropdown list. I have attached the template to this BZ, it should be pretty easy for you to re-produce. just try to launch a stack using the template in horizon.