Hi, everyone:

I tried to build an instance on the compute node but failed. I am sure that every necessary connection has been built.

And I found the same error information on the controller node and the compute node , in /var/log/neutron/linuxbride-agent.log

That is information:

INFO neutron.common.config [-] Logging enabled!

2021-04-07 11:30:52.866 2182 INFO neutron.common.config [-] /usr/bin/neutron-linuxbridge-agent version 17.1.0

2021-04-07 11:30:52.867 2182 INFO neutron.plugins.ml2.drivers.linuxbridge.agent.linuxbridge_neutron_agent [-] Interface mappings: {'provider': 'ens160'}

2021-04-07 11:30:52.867 2182 INFO neutron.plugins.ml2.drivers.linuxbridge.agent.linuxbridge_neutron_agent [-] Bridge mappings: {}

2021-04-07 11:30:52.868 2182 INFO oslo.privsep.daemon [-] Running privsep helper: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'privsep-helper', '--config-file', '/usr/share/neutron/neutron-dist.conf', '--config-file', '/etc/neutron/neutron.conf', '--config-file', '/etc/neutron/plugins/ml2/linuxbridge_agent.ini', '--config-dir', '/etc/neutron/conf.d/neutron-linuxbridge-agent', '--privsep_context', 'neutron.privileged.default', '--privsep_sock_path', '/tmp/tmpm5d0ytiv/privsep.sock']

2021-04-07 11:30:53.346 2182 CRITICAL oslo.privsep.daemon [-] privsep helper command exited non-zero (1)

2021-04-07 11:30:53.346 2182 CRITICAL neutron [-] Unhandled error: oslo_privsep.daemon.FailedToDropPrivileges: privsep helper command exited non-zero (1)

2021-04-07 11:30:53.346 2182 ERROR neutron Traceback (most recent call last):

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/bin/neutron-linuxbridge-agent", line 10, in <module>

2021-04-07 11:30:53.346 2182 ERROR neutron     sys.exit(main())

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/neutron/cmd/eventlet/plugins/linuxbridge_neutron_agent.py", line 28, in main

2021-04-07 11:30:53.346 2182 ERROR neutron     agent_main.main()

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py", line 1052, in main

2021-04-07 11:30:53.346 2182 ERROR neutron     manager = LinuxBridgeManager(bridge_mappings, interface_mappings)

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py", line 79, in __init__

2021-04-07 11:30:53.346 2182 ERROR neutron     self.validate_interface_mappings()

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py", line 94, in validate_interface_mappings

2021-04-07 11:30:53.346 2182 ERROR neutron     if not ip_lib.device_exists(interface):

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/neutron/agent/linux/ip_lib.py", line 748, in device_exists

2021-04-07 11:30:53.346 2182 ERROR neutron     return IPDevice(device_name, namespace=namespace).exists()

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/neutron/agent/linux/ip_lib.py", line 328, in exists

2021-04-07 11:30:53.346 2182 ERROR neutron     return privileged.interface_exists(self.name, self.namespace)

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/oslo_privsep/priv_context.py", line 246, in _wrap

2021-04-07 11:30:53.346 2182 ERROR neutron     self.start()

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/oslo_privsep/priv_context.py", line 258, in start

2021-04-07 11:30:53.346 2182 ERROR neutron     channel = daemon.RootwrapClientChannel(context=self)

2021-04-07 11:30:53.346 2182 ERROR neutron   File "/usr/lib/python3.6/site-packages/oslo_privsep/daemon.py", line 367, in __init__

2021-04-07 11:30:53.346 2182 ERROR neutron     raise FailedToDropPrivileges(msg)

2021-04-07 11:30:53.346 2182 ERROR neutron oslo_privsep.daemon.FailedToDropPrivileges: privsep helper command exited non-zero (1)

2021-04-07 11:30:53.346 2182 ERROR neutron

And it is the configuration in /etc/sudoer.d/neutron below:

Defaults:neutron !requiretty

neutron ALL = (root) NOPASSWD: /usr/bin/neutron-rootwrap /etc/neutron/rootwrap.conf *

neutron ALL = (root) NOPASSWD: /usr/bin/neutron-rootwrap-daemon /etc/neutron/rootwrap.conf

I googled for the solution but they didn’t matter. How can I solve this problem? Thanks for your advicement!