open stack floating ip and fixed ip

 https://mindmajix.com/openstack/manually-associating-dissociating-floating-ips-tenants

A floating IP address allows the instance to be publicly accessible. Each instance has a private, fixed IP address and can also have a public, or a floating IP address.
Floating IP addresses allow you to direct ingress network traffic to your OpenStack instances. They are associated with instances in addition to their fixed IP addresses.

"addresses":{

• "my_instance":[
  1. {
     • "version":4,
     • "addr":"192.168.11.50",
     • "OS-EXT-IPS:type":"fixed",
     • "OS-EXT-IPS-MAC:mac_addr":"1a:26:3b:4c:7d:gf"
     },
  2. {
     • "version":4,
     • "addr":"10.90.253.61",
     • "OS-EXT-IPS:type":"floating",
     • "OS-EXT-IPS-MAC:mac_addr":"1a:26:3b:4c:7d:gf"
     }
  ]

}

how to associate floating ip :

https://docs.openstack.org/ocata/user-guide/cli-manage-ip-addresses.html