How to reach a OPENSTACK instance directly without using floating IP

Question

I looking for a scenario where i can reach a instance created in a OPENSTACK Rocky version with an IP directly on the network created (inst-1 launched on 172.6.0.0/24 network) got an ip address of 172.6.0.5 So i want to ping 172.6.0.5 directly from controller machine without using the floating ip.

I know the provider network concept by associating a floating ip for the instance to reach the VM externally. But i am checking for the other approach to directly get access the VM IP from controller. Can someone help me out if you have any suggestion on this.

Thanks in advance.

Answer 1

You need a route to the tenant network to which the instance is attached. In case the external bridge, often named br-ex, is located on that controller, just create a suitable routing table entry. Assuming the subnet is 172.6.0.0/24, this command takes care of it:

ip route add 172.6.0.0/24 dev br-ex

How to make this route persistent depends on the network management tool used on that server.

Note that this only gives you access to that instance from that controller, not from other devices.