I have known that to set an Availability Zone, I should set the node_availability_zone field in nova.conf. But I have two questions about the Availability Zone.

1. How to create or modify Availability Zone by api? The nova command line tool only support availability-zone-list command, lacking creating and modifying command. If this is by design, why?

2. When a host firstly register to controller node as nova zone, modifying the nova.conf to set node_availability_zone to "test_zone" cannot change metadata. The zone is still named as nova in "nova availability-zone-list" and the compute node still belong to nova zone in "nova-manage service list". Is there a way to change a host to another availability zone?

Thanks for your reading and sorry for my poor English.