Comment 9 for bug 1080846

It does appear to be the PID:

 sudo /usr/local/bin/quantum-rootwrap /etc/quantum/rootwrap.conf ip netns exec qdhcp-788fd34d-6201-49c6-bb0d-928eec877607 kill -HUP 22774
Unauthorized command: ip netns exec qdhcp-788fd34d-6201-49c6-bb0d-928eec877607 kill -HUP 22774
stack@ubuntu:~/devstack$ ps fax | grep 22774
21710 pts/1 S+ 0:00 | \_ grep --color=auto 22774
stack@ubuntu:~/devstack$ ps fax | grep dhcp
  818 ? Ss 0:00 dhclient -1 -v -pf /run/dhclient.eth0.pid -lf /var/lib/dhcp/dhclient.eth0.leases eth0
21930 pts/1 S+ 0:00 | \_ grep --color=auto dhcp
22447 pts/9 S+ 0:01 | \_ python /opt/stack/quantum/bin/quantum-dhcp-agent --config-file /etc/quantum/quantum.conf --config-file=/etc/quantum/dhcp_agent.ini
28009 ? S 0:01 dnsmasq --conf-file= --port=0 --enable-tftp --tftp-root=/tftpboot --dhcp-boot=pxelinux.0 --bind-interfaces --pid-file=/var/run/dnsmasq.pid --interface=eth1 --dhcp-range=192.0.2.65,192.0.2.127,255.255.255.0
stack@ubuntu:~/devstack$ sudo /usr/local/bin/quantum-rootwrap /etc/quantum/rootwrap.conf ip netns exec qdhcp-788fd34d-6201-49c6-bb0d-928eec877607 kill -HUP 28009