We have JUNO openstack running with --allinone setup and everything is good. i have did following to setup flat network directly integrate my VM with existing network.

openstack-config --set /etc/neutron/plugins/openvswitch/ovs_neutron_plugin.ini ovs bridge_mappings extnet:br-ex openstack-config --set /etc/neutron/plugin.ini ml2 type_drivers vxlan,flat,vlan

Restart neutron* services

neutron net-create external_network --provider:network_type flat --provider:physical_network extnet --router:external --shared

neutron subnet-create --name public_subnet --enable_dhcp=False --allocation-pool=start=192.168.1.10,end=192.168.1.20 \ --gateway=192.168.1.1 external_network 192.168.1.0/24

Everything working fine. But once it create VM it reserve IP address and next VM will pick next IP so on and on...

How do i free old ip which i used before. I have only 10 IPs currently. Please advice how i can free ips which i used in past?

I am not using following methods.

floating IP etc.. DHCP IP etc..

My network is just Flat network.