It just happened without any restart, few instances on the same network across different compute nodes lost Internet connectivity.

Logs about the MAC address of one of the instance:

2018-10-16 20:48:52.245 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] ofctl request version=0x4,msg_type=0x12,msg_len=0x38,xid=0xb26581cc,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=25,type=1) result [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=63937013,cookie=1865276097587823870,duration_nsec=225000000,duration_sec=9052,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:cc:af:31', 'in_port': 67}),packet_count=122641,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=144000000,duration_sec=9052,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:d7:bd:b7', 'in_port': 201}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=116000000,duration_sec=9052,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2b:3e:10', 'in_port': 68}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=870,cookie=1865276097587823870,duration_nsec=89000000,duration_sec=9052,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2c:6e:6b', 'in_port': 252}),packet_count=15,priority=2,table_id=25), OFPFlowStats(byte_count=236338958,cookie=1865276097587823870,duration_nsec=32000000,duration_sec=9052,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:a8:60:0b', 'in_port': 307}),pac
ket_count=338352,priority=2,table_id=25), OFPFlowStats(byte_count=368190,cookie=1865276097587823870,duration_nsec=3000000,duration_sec=9052,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:73:cd:9d', 'in_port': 112}),packet_count=1462,priority=2,table_id=25), OFPFlowStats(byte_count=145838491,cookie=1865276097587823870,duration_nsec=269000000,duration_sec=8876,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:77:81:ec', 'in_port': 57}),packet_count=67025,priority=2,table_id=25), OFPFlowStats(byte_count=581037,cookie=1865276097587823870,duration_nsec=223000000,duration_sec=8876,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:14:e2:2f', 'in_port': 89}),packet_count=9460,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=2000000,duration_sec=0,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:65:41:72', 'in_port': 310}),packet_count=0,priority=2,table_id=25)],flags=0,type=1)] _send_msg /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:99
2018-10-16 20:49:00.900 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] ofctl request version=0x4,msg_type=0x12,msg_len=0x38,xid=0xb26581e4,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=25,type=1) result [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=63970501,cookie=1865276097587823870,duration_nsec=880000000,duration_sec=9060,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:cc:af:31', 'in_port': 67}),packet_count=122797,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=799000000,duration_sec=9060,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:d7:bd:b7', 'in_port': 201}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=771000000,duration_sec=9060,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2b:3e:10', 'in_port': 68}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=870,cookie=1865276097587823870,duration_nsec=744000000,duration_sec=9060,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2c:6e:6b', 'in_port': 252}),packet_count=15,priority=2,table_id=25), OFPFlowStats(byte_count=236493249,cookie=1865276097587823870,duration_nsec=687000000,duration_sec=9060,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:a8:60:0b', 'in_port': 307}),p
acket_count=338584,priority=2,table_id=25), OFPFlowStats(byte_count=368190,cookie=1865276097587823870,duration_nsec=658000000,duration_sec=9060,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:73:cd:9d', 'in_port': 112}),packet_count=1462,priority=2,table_id=25), OFPFlowStats(byte_count=145856976,cookie=1865276097587823870,duration_nsec=924000000,duration_sec=8884,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:77:81:ec', 'in_port': 57}),packet_count=67037,priority=2,table_id=25), OFPFlowStats(byte_count=581373,cookie=1865276097587823870,duration_nsec=878000000,duration_sec=8884,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:14:e2:2f', 'in_port': 89}),packet_count=9468,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=2000000,duration_sec=0,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:65:41:72', 'in_port': 310}),packet_count=0,priority=2,table_id=25)],flags=0,type=1)] _send_msg /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:99
2018-10-16 20:49:07.431 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] ofctl request version=0x4,msg_type=0x12,msg_len=0x38,xid=0xb26581fc,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=25,type=1) result [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=64037567,cookie=1865276097587823870,duration_nsec=411000000,duration_sec=9067,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:cc:af:31', 'in_port': 67}),packet_count=122967,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=330000000,duration_sec=9067,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:d7:bd:b7', 'in_port': 201}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=302000000,duration_sec=9067,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2b:3e:10', 'in_port': 68}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=870,cookie=1865276097587823870,duration_nsec=275000000,duration_sec=9067,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2c:6e:6b', 'in_port': 252}),packet_count=15,priority=2,table_id=25), OFPFlowStats(byte_count=236580030,cookie=1865276097587823870,duration_nsec=218000000,duration_sec=9067,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:a8:60:0b', 'in_port': 307}),p
acket_count=338748,priority=2,table_id=25), OFPFlowStats(byte_count=368190,cookie=1865276097587823870,duration_nsec=189000000,duration_sec=9067,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:73:cd:9d', 'in_port': 112}),packet_count=1462,priority=2,table_id=25), OFPFlowStats(byte_count=145880683,cookie=1865276097587823870,duration_nsec=455000000,duration_sec=8891,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:77:81:ec', 'in_port': 57}),packet_count=67067,priority=2,table_id=25), OFPFlowStats(byte_count=581625,cookie=1865276097587823870,duration_nsec=409000000,duration_sec=8891,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:14:e2:2f', 'in_port': 89}),packet_count=9474,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=2000000,duration_sec=0,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:65:41:72', 'in_port': 310}),packet_count=0,priority=2,table_id=25)],flags=0,type=1)] _send_msg /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:99
2018-10-16 20:49:14.108 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] ofctl request version=0x4,msg_type=0x12,msg_len=0x38,xid=0xb2658214,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=25,type=1) result [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=64055129,cookie=1865276097587823870,duration_nsec=88000000,duration_sec=9074,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:cc:af:31', 'in_port': 67}),packet_count=123100,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=7000000,duration_sec=9074,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:d7:bd:b7', 'in_port': 201}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=979000000,duration_sec=9073,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2b:3e:10', 'in_port': 68}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=870,cookie=1865276097587823870,duration_nsec=952000000,duration_sec=9073,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2c:6e:6b', 'in_port': 252}),packet_count=15,priority=2,table_id=25), OFPFlowStats(byte_count=236735457,cookie=1865276097587823870,duration_nsec=895000000,duration_sec=9073,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:a8:60:0b', 'in_port': 307}),pack
et_count=338984,priority=2,table_id=25), OFPFlowStats(byte_count=368190,cookie=1865276097587823870,duration_nsec=866000000,duration_sec=9073,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:73:cd:9d', 'in_port': 112}),packet_count=1462,priority=2,table_id=25), OFPFlowStats(byte_count=145881875,cookie=1865276097587823870,duration_nsec=132000000,duration_sec=8898,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:77:81:ec', 'in_port': 57}),packet_count=67079,priority=2,table_id=25), OFPFlowStats(byte_count=581877,cookie=1865276097587823870,duration_nsec=86000000,duration_sec=8898,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:14:e2:2f', 'in_port': 89}),packet_count=9480,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=2000000,duration_sec=0,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:65:41:72', 'in_port': 310}),packet_count=0,priority=2,table_id=25)],flags=0,type=1)] _send_msg /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:99
2018-10-16 20:49:20.626 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] ofctl request version=0x4,msg_type=0x12,msg_len=0x38,xid=0xb265822c,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=25,type=1) result [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=64060723,cookie=1865276097587823870,duration_nsec=606000000,duration_sec=9080,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:cc:af:31', 'in_port': 67}),packet_count=123183,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=525000000,duration_sec=9080,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:d7:bd:b7', 'in_port': 201}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=497000000,duration_sec=9080,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2b:3e:10', 'in_port': 68}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=870,cookie=1865276097587823870,duration_nsec=470000000,duration_sec=9080,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2c:6e:6b', 'in_port': 252}),packet_count=15,priority=2,table_id=25), OFPFlowStats(byte_count=236820418,cookie=1865276097587823870,duration_nsec=413000000,duration_sec=9080,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:a8:60:0b', 'in_port': 307}),p
acket_count=339149,priority=2,table_id=25), OFPFlowStats(byte_count=368190,cookie=1865276097587823870,duration_nsec=384000000,duration_sec=9080,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:73:cd:9d', 'in_port': 112}),packet_count=1462,priority=2,table_id=25), OFPFlowStats(byte_count=145882744,cookie=1865276097587823870,duration_nsec=650000000,duration_sec=8904,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:77:81:ec', 'in_port': 57}),packet_count=67089,priority=2,table_id=25), OFPFlowStats(byte_count=582129,cookie=1865276097587823870,duration_nsec=604000000,duration_sec=8904,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:14:e2:2f', 'in_port': 89}),packet_count=9486,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=2000000,duration_sec=0,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:65:41:72', 'in_port': 310}),packet_count=0,priority=2,table_id=25)],flags=0,type=1)] _send_msg /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:99
2018-10-16 20:49:27.110 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.openflow.native.ofswitch [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] ofctl request version=0x4,msg_type=0x12,msg_len=0x38,xid=0xb2658244,OFPFlowStatsRequest(cookie=0,cookie_mask=0,flags=0,match=OFPMatch(oxm_fields={}),out_group=4294967295,out_port=4294967295,table_id=25,type=1) result [OFPFlowStatsReply(body=[OFPFlowStats(byte_count=64066487,cookie=1865276097587823870,duration_nsec=90000000,duration_sec=9087,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:cc:af:31', 'in_port': 67}),packet_count=123265,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=9000000,duration_sec=9087,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:d7:bd:b7', 'in_port': 201}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=981000000,duration_sec=9086,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2b:3e:10', 'in_port': 68}),packet_count=0,priority=2,table_id=25), OFPFlowStats(byte_count=870,cookie=1865276097587823870,duration_nsec=954000000,duration_sec=9086,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:2c:6e:6b', 'in_port': 252}),packet_count=15,priority=2,table_id=25), OFPFlowStats(byte_count=236974733,cookie=1865276097587823870,duration_nsec=897000000,duration_sec=9086,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:a8:60:0b', 'in_port': 307}),pack
et_count=339381,priority=2,table_id=25), OFPFlowStats(byte_count=368190,cookie=1865276097587823870,duration_nsec=868000000,duration_sec=9086,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:73:cd:9d', 'in_port': 112}),packet_count=1462,priority=2,table_id=25), OFPFlowStats(byte_count=145907750,cookie=1865276097587823870,duration_nsec=134000000,duration_sec=8911,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:77:81:ec', 'in_port': 57}),packet_count=67130,priority=2,table_id=25), OFPFlowStats(byte_count=582381,cookie=1865276097587823870,duration_nsec=88000000,duration_sec=8911,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:14:e2:2f', 'in_port': 89}),packet_count=9492,priority=2,table_id=25), OFPFlowStats(byte_count=0,cookie=1865276097587823870,duration_nsec=2000000,duration_sec=0,flags=0,hard_timeout=0,idle_timeout=0,instructions=[OFPInstructionGotoTable(len=8,table_id=60,type=1)],length=80,match=OFPMatch(oxm_fields={'eth_src': 'fa:16:3e:65:41:72', 'in_port': 310}),packet_count=0,priority=2,table_id=25)],flags=0,type=1)] _send_msg /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/openflow/native/ofswitch.py:99

Log about the port UUID of the same instance than above:

2018-10-16 18:21:00.098 7 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Configuration for devices [u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'1788be7a-99cb-42b4-b938-f555170ddb55'] failed!
2018-10-16 20:48:43.419 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'1788be7a-99cb-42b4-b938-f555170ddb55', u'cc3883d5-be1c-4e58-8261-b4fe8176187c']), 'removed': set([]), 'added': set([u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7'])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:48:56.765 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7']), 'updated': set(['63f62cc3-803c-4ba2-aa12-a5f5c8e40df7'])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:49:03.294 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7'])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:49:09.990 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7'])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:49:16.496 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7'])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:49:22.995 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7'])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:53:21.866 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([]), 'updated': set([])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106
2018-10-16 20:55:43.033 7 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e043990b-2cff-43bf-a0e6-65b24421ec4b - - - - -] Starting to process devices in:{'current': set([u'3d3b1223-ef5d-4fb4-9bc9-9d295d06f9dc', u'7353416f-4512-47cd-9082-1e42aa9d5e2c', u'933af749-2e31-4f6a-a602-eb7eacff2f1d', u'07980f2e-c6cd-4bbb-9115-7a688da7a412', u'9d977e28-c41c-49f9-be05-fb39d3a021e3', u'52e5f3b1-d810-4dcf-b770-5cb0605c48bf', u'1254d0ef-a51a-407c-b056-54d7d1af8867', u'63f62cc3-803c-4ba2-aa12-a5f5c8e40df7', u'712071c2-d58e-45e0-90d9-c17c8c462d9c', u'15259e8b-6495-4e43-8042-a575df72c6d7', u'cc3883d5-be1c-4e58-8261-b4fe8176187c', u'9a662f16-d33c-4946-b0d5-5368fa5607d7', u'6e03427d-668d-4008-bf72-1f884b26a07c', u'38a1d9ef-6c8a-4434-a4fe-37fd3f197d74', u'120e74f2-5f3f-4bfc-900e-2594592d43f6', u'5ce77d3a-a8d5-41b2-bbf3-5703d05a22a7', u'883d2447-6cee-4609-bc3f-492d0ae0dcf0', u'2d6a9ef8-0a07-4703-90b3-4347378f9265', u'866dfa65-696b-43f8-9a3c-529ee1d3293b', u'c6ef2cc7-b6d5-401c-9163-087c264d0218', u'db76a106-7c9d-4a2a-a986-bdee01c7cea5', u'1788be7a-99cb-42b4-b938-f555170ddb55']), 'removed': set([]), 'added': set([]), 'updated': set([])} rpc_loop /var/lib/kolla/venv/local/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:2106

Open vSwitch logs matching the time range:

2018-10-16T18:17:01.487Z|54333|bridge|INFO|bridge br-tun: added interface vxlan-0a830848 on port 120
2018-10-16T18:21:33.360Z|54344|connmgr|INFO|br-int<->tcp:127.0.0.1:6633: 90 flow_mods in the 18 s starting 56 s ago (20 adds, 70 deletes)
2018-10-16T18:21:47.357Z|54345|connmgr|INFO|br-tun<->tcp:127.0.0.1:6633: 8 flow_mods in the 53 s starting 54 s ago (7 adds, 1 deletes)
2018-10-16T20:49:54.436Z|54356|connmgr|INFO|br-int<->tcp:127.0.0.1:6633: 50 flow_mods in the 29 s starting 56 s ago (40 adds, 10 deletes)

Flows status from our script: http://paste.openstack.org/show/732350/

Hope it helps.