My single node openstack devstack setup is currently running perfectly, but when I change hostname of my system i.e. I made changes in /etc/hosts and /etc/hostname to set a new hostname. After rebooting system setup is running with error of oslo messaging saying

ERROR oslo.messaging._drivers.impl_rabbit [-] AMQP server 127.0.0.1:5672 closed the connection. Check login credentials: Socket closed

On running nova list error shows up saying

ERROR (ClientException): The server has either erred or is incapable of performing the requested operation. (HTTP 500) (Request-ID: req-c4251e32-c59e-4ebf-aad1-9f13236f41a1)

Any idea what is potential solution to this.

PS: If I revert back the changes, it start running perfectly.