Specifying static IP for neutron router external gateway port
Whilst it's easy to manually control the IP address assigned to a router's internal-facing port(s) I'm yet to find a way to achieve the same with the port used as the "External Gateway", whether from Horizon or the CLI.
One naive way from Horizon would have been to manually create the external port (using "Add Interface", specifying its IP as required, then attempt to set it using "Set Gateway"; alas this fails with Failed to set gateway: Bad router request: Router already has a port on subnet xxx
. I've tried this approach with both Horizon and the neutron CLI with no luck.