I think I have met the same issue before, you can check quantum dhcp log. If you find the log like following:

RuntimeError: Command: ['sudo', '/usr/bin/quantum-rootwrap', '/etc/quantum/rootwrap.conf', 'ip', 'link', 'set', 'qg-dd9483f7-7d', 'address', 'fa:16:3e:a9:07:58']Exit code: 2Stdout: ''Stderr: 'RTNETLINK answers: Device or resource busy\n'

You can solve this issue refer to the following URL: http://blog.csdn.net/maoliping455mlp455/article/details/9331375 (http://blog.csdn.net/maoliping455mlp4...)

I think I have met the same issue before, you can check quantum dhcp log. If you find the log like following:

RuntimeError: Command: ['sudo', '/usr/bin/quantum-rootwrap', '/etc/quantum/rootwrap.conf', 'ip', 'link', 'set', 'qg-dd9483f7-7d', 'address', 'fa:16:3e:a9:07:58']Exit code: 2Stdout: ''Stderr: 'RTNETLINK answers: Device or resource busy\n'

You can solve this issue refer to the following URL: http://blog.csdn.net/maoliping455mlp455/article/details/9331375 (http://blog.csdn.net/maoliping455mlp4...)

I think I have met the same issue before, you can check quantum dhcp log. If you find the log like following:

RuntimeError: Command: ['sudo', '/usr/bin/quantum-rootwrap', '/etc/quantum/rootwrap.conf', 'ip', 'link', 'set', 'qg-dd9483f7-7d', 'address', 'fa:16:3e:a9:07:58']Exit code: 2Stdout: ''Stderr: 'RTNETLINK answers: Device or resource busy\n'

You can solve this issue refer to the following URL: http://blog.csdn.net/maoliping455mlp455/article/details/9331375 (http://blog.csdn.net/maoliping455mlp4...)

I think I have met the same issue before, you can check quantum dhcp log. If you find the log like following:

RuntimeError: Command: ['sudo', '/usr/bin/quantum-rootwrap', '/etc/quantum/rootwrap.conf', 'ip', 'link', 'set', 'qg-dd9483f7-7d', 'address', 'fa:16:3e:a9:07:58']Exit code: 2Stdout: ''Stderr: 'RTNETLINK answers: Device or resource busy\n'

You can solve this issue refer to the following URL: http://blog.csdn.net/maoliping455mlp455/article/details/9331375 (http://blog.csdn.net/maoliping455mlp4...)

Not sure I have unstood what you said... ^_^ So you mean you use nova-network? The log shows that your VM has send dhcp req, but it does not get response from dnsmasq. You can run dhcpc in your VM in VNC, and use tcpdump to see where the req packet be, then you can see what's the problem. BTW, after you kill dnsmasq and restart nova-network, do you mean your dnsmasq is not up? You can boot another VM, I think dnsmasq should be up. Otherwise, you need to check if there is any error message in log...