After I create an instance on OpenStack with the REST API Using the Nova endpoint the operation succeeds with the server id reference. If I immediately try to get any of the details of the network interfaces (using the /servers/server-id/ips) I get nothing, not even an error message that the resource is busy. If I put an arbitrary 30 second wait, I'll get the details. Is there any API call that can use on OpenStack to get a "is ready" state after a creation?
If there is no operation to determine that the server is ready, then is there a recommended wait time in the documentation?
You should wait for the instance to be in the "active" state. That's when the instance has been fully built, including network. You're probably hitting the instance while its still in the "building" state.