版本Ubuntu 12.04 Icehouse

 /var/log/neutron/openvswitch-agent.log

Stderr: 'sudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: 3 incorrect password attempts\n'

2015-12-18 15:06:45.459 28397 ERROR neutron.agent.linux.ovs_lib [-] Unable to execute ['ovs-vsctl', '--timeout=10', '--', 'set-fail-mode', 'br-int', 'secure']. Exception: 
Command: ['sudo', 'ovs-vsctl', '--timeout=10', '--', 'set-fail-mode', 'br-int', 'secure']
Exit code: 1
Stdout: ''
Stderr: 'sudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: 3 incorrect password attempts\n'
2015-12-18 15:06:45.459 28397 CRITICAL neutron [-] 
Command: ['sudo', 'ovs-vsctl', '--timeout=10', '--', 'set-fail-mode', 'br-int', 'secure']
Exit code: 1
Stdout: ''
Stderr: 'sudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: no tty present and no askpass program specified\nSorry, try again.\nsudo: 3 incorrect password attempts\n'

 ERROR neutron.agent.linux.ovs_lib [-] Unable to execute ['ovs-vsctl', '--timeout=10'

解决办法：

/etc/neutron/neutron.conf

添加如下：

[agent]
root_helper = sudo /usr/bin/neutron-rootwrap /etc/neutron/rootwrap.conf