It is easy to reproduce, I created four vms and then delete some of them, the agent will crash:



Stdout: '{attached-mac="fa:16:3e:0e:02:0a", iface-id="d916a3d8-4140-4742-8fde-45759ae07aac", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 list-ports br-int
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 list-ports br-int
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'list-ports', 'br-int']
Exit code: 0
Stdout: 'int-br-eth1-1\nint-br-eth1-2\nqr-9b44fdbe-9c\ntap216a1c49-a6\ntap3d8ab559-59\ntap6bc96b0b-ca\ntap8359faa8-e1\ntapc041f805-a2\ntapd916a3d8-41\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'list-ports', 'br-int']
Exit code: 0
Stdout: 'int-br-eth1-1\nint-br-eth1-2\nqr-9b44fdbe-9c\ntap216a1c49-a6\ntap3d8ab559-59\ntap6bc96b0b-ca\ntap8359faa8-e1\ntapc041f805-a2\ntapd916a3d8-41\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-1 external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-1 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-1', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-1', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-2 external_ids
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-2 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-2', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-2', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface qr-9b44fdbe-9c external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface qr-9b44fdbe-9c external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'qr-9b44fdbe-9c', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:5a:5f:2a", iface-id="9b44fdbe-9c97-4a2f-b08c-17a7a36b4cfe", iface-status=active}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'qr-9b44fdbe-9c', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:5a:5f:2a", iface-id="9b44fdbe-9c97-4a2f-b08c-17a7a36b4cfe", iface-status=active}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tap216a1c49-a6 external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tap216a1c49-a6 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap216a1c49-a6', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:8b:6e:98", iface-id="216a1c49-a6db-4be7-a12e-e95ebe91f2c5", iface-status=active}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap216a1c49-a6', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:8b:6e:98", iface-id="216a1c49-a6db-4be7-a12e-e95ebe91f2c5", iface-status=active}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tap3d8ab559-59 external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tap3d8ab559-59 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap3d8ab559-59', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:df:1a:e1", iface-id="3d8ab559-5932-4dc5-873f-5424cb37263e", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap3d8ab559-59', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:df:1a:e1", iface-id="3d8ab559-5932-4dc5-873f-5424cb37263e", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tap6bc96b0b-ca external_ids
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tap6bc96b0b-ca external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap6bc96b0b-ca', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:f0:a0:1b", iface-id="6bc96b0b-cab7-4c46-8e9c-7b0fa0385825", iface-status=active, vm-uuid="7a95308a-ff1b-4ad3-ae69-094585f9ed1f"}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap6bc96b0b-ca', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:f0:a0:1b", iface-id="6bc96b0b-cab7-4c46-8e9c-7b0fa0385825", iface-status=active, vm-uuid="7a95308a-ff1b-4ad3-ae69-094585f9ed1f"}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tap8359faa8-e1 external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tap8359faa8-e1 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap8359faa8-e1', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:6c:52:e3", iface-id="8359faa8-e1f6-4e73-b36c-10fd2d431100", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap8359faa8-e1', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:6c:52:e3", iface-id="8359faa8-e1f6-4e73-b36c-10fd2d431100", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tapc041f805-a2 external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tapc041f805-a2 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:dc:0e:3d", iface-id="c041f805-a296-43f8-9f3b-6a42f1759943", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:dc:0e:3d", iface-id="c041f805-a296-43f8-9f3b-6a42f1759943", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tapd916a3d8-41 external_ids
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tapd916a3d8-41 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapd916a3d8-41', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:0e:02:0a", iface-id="d916a3d8-4140-4742-8fde-45759ae07aac", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
2012-09-17 14:22:30    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapd916a3d8-41', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:0e:02:0a", iface-id="d916a3d8-4140-4742-8fde-45759ae07aac", iface-status=active, vm-uuid="e75ce4d9-ebf6-4b49-bf0f-5ffefd07c479"}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 list-ports br-int
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 list-ports br-int
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'list-ports', 'br-int']
Exit code: 0
Stdout: 'int-br-eth1-1\nint-br-eth1-2\nqr-9b44fdbe-9c\ntap216a1c49-a6\ntap6bc96b0b-ca\ntapc041f805-a2\ntapd916a3d8-41\n'
Stderr: ''
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'list-ports', 'br-int']
Exit code: 0
Stdout: 'int-br-eth1-1\nint-br-eth1-2\nqr-9b44fdbe-9c\ntap216a1c49-a6\ntap6bc96b0b-ca\ntapc041f805-a2\ntapd916a3d8-41\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-1 external_ids
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-1 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-1', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-1', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-2 external_ids
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface int-br-eth1-2 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-2', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'int-br-eth1-2', 'external_ids']
Exit code: 0
Stdout: '{}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface qr-9b44fdbe-9c external_ids
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface qr-9b44fdbe-9c external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'qr-9b44fdbe-9c', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:5a:5f:2a", iface-id="9b44fdbe-9c97-4a2f-b08c-17a7a36b4cfe", iface-status=active}\n'
Stderr: ''
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'qr-9b44fdbe-9c', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:5a:5f:2a", iface-id="9b44fdbe-9c97-4a2f-b08c-17a7a36b4cfe", iface-status=active}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tap216a1c49-a6 external_ids
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tap216a1c49-a6 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap216a1c49-a6', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:8b:6e:98", iface-id="216a1c49-a6db-4be7-a12e-e95ebe91f2c5", iface-status=active}\n'
Stderr: ''
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap216a1c49-a6', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:8b:6e:98", iface-id="216a1c49-a6db-4be7-a12e-e95ebe91f2c5", iface-status=active}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tap6bc96b0b-ca external_ids
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tap6bc96b0b-ca external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap6bc96b0b-ca', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:f0:a0:1b", iface-id="6bc96b0b-cab7-4c46-8e9c-7b0fa0385825", iface-status=active, vm-uuid="7a95308a-ff1b-4ad3-ae69-094585f9ed1f"}\n'
Stderr: ''
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tap6bc96b0b-ca', 'external_ids']
Exit code: 0
Stdout: '{attached-mac="fa:16:3e:f0:a0:1b", iface-id="6bc96b0b-cab7-4c46-8e9c-7b0fa0385825", iface-status=active, vm-uuid="7a95308a-ff1b-4ad3-ae69-094585f9ed1f"}\n'
Stderr: ''
DEBUG:quantum.agent.linux.utils:Running command: sudo ovs-vsctl --timeout=2 get Interface tapc041f805-a2 external_ids
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] Running command: sudo ovs-vsctl --timeout=2 get Interface tapc041f805-a2 external_ids
DEBUG:quantum.agent.linux.utils:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']
Exit code: 1
Stdout: ''
Stderr: 'ovs-vsctl: no row "tapc041f805-a2" in table Interface\n'
2012-09-17 14:22:32    DEBUG [quantum.agent.linux.utils] 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']
Exit code: 1
Stdout: ''
Stderr: 'ovs-vsctl: no row "tapc041f805-a2" in table Interface\n'
2012-09-17 14:22:32    ERROR [quantum.agent.linux.ovs_lib] Unable to execute ['ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']. Exception: 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']
Exit code: 1
Stdout: ''
Stderr: 'ovs-vsctl: no row "tapc041f805-a2" in table Interface\n'
ERROR:quantum.agent.linux.ovs_lib:Unable to execute ['ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']. Exception: 
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'get', 'Interface', 'tapc041f805-a2', 'external_ids']
Exit code: 1
Stdout: ''
Stderr: 'ovs-vsctl: no row "tapc041f805-a2" in table Interface\n'
Traceback (most recent call last):
  File "/home/gongysh/git/quantum/bin/quantum-openvswitch-agent", line 24, in <module>
    main()
  File "/home/gongysh/git/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 817, in main
    plugin.daemon_loop(db_connection_url)
  File "/home/gongysh/git/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 777, in daemon_loop
    self.rpc_loop()
  File "/home/gongysh/git/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 758, in rpc_loop
    port_info = self.update_ports(ports)
  File "/home/gongysh/git/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 651, in update_ports
    ports = self.int_br.get_vif_port_set()
  File "/home/gongysh/git/quantum/quantum/agent/linux/ovs_lib.py", line 242, in get_vif_port_set
    if "iface-id" in external_ids and "attached-mac" in external_ids:
TypeError: argument of type 'NoneType' is not iterable