 <p>I'm having the same problem now. I'm deploying OpenStack on 2 nodes, and instances can be accessed by VNC (I think it's more or less the same with devstack on one node).</p> <p>The problem is I didn't assigned floating IP to a VM. Plus, br-ex must add a physical interface that connect to outside network. You can check by typing:</p> <pre><code>sudo ovs-vsctl show </code></pre> <p>And see if br-ex have an interface or not. If not, try to add an interface:</p> <pre><code>sudo ovs-vsctl add-port br-ex eth0 </code></pre> <p>Hope it will help</p>