Same situation here. cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=16.04 DISTRIB_CODENAME=xenial DISTRIB_DESCRIPTION="Ubuntu 16.04.1 LTS" dpkg -l | egrep 'nova|neutron' ii neutron-common 2:8.3.0-0ubuntu1 all Neutron is a virtual network service for Openstack - common ii neutron-l3-agent 2:8.3.0-0ubuntu1 all Neutron is a virtual network service for Openstack - l3 agent ii neutron-metadata-agent 2:8.3.0-0ubuntu1 all Neutron is a virtual network service for Openstack - metadata agent ii neutron-openvswitch-agent 2:8.3.0-0ubuntu1 all Neutron is a virtual network service for Openstack - Open vSwitch plugin agent ii nova-common 2:13.1.2-0ubuntu2 all OpenStack Compute - common files ii nova-compute 2:13.1.2-0ubuntu2 all OpenStack Compute - compute node base ii nova-compute-kvm 2:13.1.2-0ubuntu2 all OpenStack Compute - compute node (KVM) ii nova-compute-libvirt 2:13.1.2-0ubuntu2 all OpenStack Compute - compute node libvirt support 2016-11-10 19:43:43.044 6664 INFO eventlet.wsgi.server [-] (6664) wsgi starting up on http:/var/lib/neutron/keepalived-state-change 2016-11-10 19:43:43.051 6664 INFO neutron.agent.l3.agent [-] L3 agent started 2016-11-10 19:43:43.054 6664 INFO neutron.agent.l3.agent [-] Agent has just been revived. Doing a full sync. 2016-11-10 19:43:56.262 6664 ERROR neutron.agent.linux.utils [-] Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "fip-5d2242e3-4ac0-4873-a752-3a504d17235d": No such file or directory 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info [-] Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "fip-5d2242e3-4ac0-4873-a752-3a504d17235d": No such file or directory 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info Traceback (most recent call last): 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/common/utils.py", line 382, in call 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info return func(*args, **kwargs) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/router_info.py", line 989, in process 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info self.process_external(agent) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_local_router.py", line 514, in process_external 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info self.create_dvr_fip_interfaces(ex_gw_port) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_local_router.py", line 545, in create_dvr_fip_interfaces 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info self.fip_ns.update_gateway_port(fip_agent_port) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_fip_ns.py", line 243, in update_gateway_port 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info ipd.route.add_gateway(gw_ip) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 690, in add_gateway 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info self._as_root([ip_version], tuple(args)) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 361, in _as_root 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info use_root_namespace=use_root_namespace) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 94, in _as_root 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info log_fail_as_error=self.log_fail_as_error) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 103, in _execute 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info log_fail_as_error=log_fail_as_error) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/utils.py", line 140, in execute 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info raise RuntimeError(msg) 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info RuntimeError: Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "fip-5d2242e3-4ac0-4873-a752-3a504d17235d": No such file or directory 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info 2016-11-10 19:43:56.274 6664 ERROR neutron.agent.l3.router_info 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent [-] Failed to process compatible router '76478ad8-f86d-4d7e-8125-c3b1f589515b' 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent Traceback (most recent call last): 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/agent.py", line 501, in _process_router_update 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self._process_router_if_compatible(router) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/agent.py", line 438, in _process_router_if_compatible 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self._process_added_router(router) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/agent.py", line 446, in _process_added_router 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent ri.process(self) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_local_router.py", line 583, in process 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent super(DvrLocalRouter, self).process(agent) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_router_base.py", line 31, in process 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent super(DvrRouterBase, self).process(agent) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/common/utils.py", line 385, in call 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self.logger(e) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 220, in __exit__ 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self.force_reraise() 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 196, in force_reraise 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent six.reraise(self.type_, self.value, self.tb) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/common/utils.py", line 382, in call 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent return func(*args, **kwargs) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/router_info.py", line 989, in process 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self.process_external(agent) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_local_router.py", line 514, in process_external 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self.create_dvr_fip_interfaces(ex_gw_port) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_local_router.py", line 545, in create_dvr_fip_interfaces 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self.fip_ns.update_gateway_port(fip_agent_port) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/l3/dvr_fip_ns.py", line 243, in update_gateway_port 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent ipd.route.add_gateway(gw_ip) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 690, in add_gateway 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent self._as_root([ip_version], tuple(args)) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 361, in _as_root 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent use_root_namespace=use_root_namespace) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 94, in _as_root 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent log_fail_as_error=self.log_fail_as_error) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 103, in _execute 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent log_fail_as_error=log_fail_as_error) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/utils.py", line 140, in execute 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent raise RuntimeError(msg) 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent RuntimeError: Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "fip-5d2242e3-4ac0-4873-a752-3a504d17235d": No such file or directory 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent 2016-11-10 19:43:56.330 6664 ERROR neutron.agent.l3.agent 2016-11-10 19:43:56.347 6664 ERROR neutron.agent.linux.utils [-] Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "fip-5d2242e3-4ac0-4873-a752-3a504d17235d": No such file or directory 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib [-] Failed sending gratuitous ARP to 10.192.233.83 on fg-1900f48a-82 in namespace fip-5d2242e3-4ac0-4873-a752-3a504d17235d 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib Traceback (most recent call last): 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 1047, in _arping 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib ip_wrapper.netns.execute(arping_cmd, check_exit_code=True) 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/ip_lib.py", line 934, in execute 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib log_fail_as_error=log_fail_as_error, **kwargs) 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib File "/usr/lib/python2.7/dist-packages/neutron/agent/linux/utils.py", line 140, in execute 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib raise RuntimeError(msg) 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib RuntimeError: Exit code: 1; Stdin: ; Stdout: ; Stderr: Cannot open network namespace "fip-5d2242e3-4ac0-4873-a752-3a504d17235d": No such file or directory 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib 2016-11-10 19:43:56.370 6664 ERROR neutron.agent.linux.ip_lib It happens irregularly so whenever I have a maintenance, I have to check if the default gateway of fip is available all the time.