在網路節點中安裝nova-compute與neutron-plugin-openvswitch-agent neutron-plugin-ml2時，nova-compute啟動正常，但當重啟計算節點後，service nova-compute restart 提示unknown instance，nova-compute.log中沒有錯誤輸出，但在openvswitch-agent.log中提示如下：ERROR neutron.agent.linux.ovsdb_monitor [-] Error received from ovsdb monitor: ovsdb-client: unix:/var/run/openvswitch/db.sock: receive failed (End of file) ERROR neutron.agent.linux.ovs_lib [-] Unable to execute ['ovs-ofctl', 'dump-flows', 'br-int', 'table=22']. Exception: Command: ['sudo', '/usr/bin/neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ovs-ofctl', 'dump-flows', 'br-int', 'table=22']Exit code: 1Stdout: ''Stderr: 'ovs-ofctl: br-int is not a bridge or a socket

我的錯誤是沒有刪除 nova.sqlite檔案，執行rm -f /var/lib/nova/nova.sqlite命令重啟nova-compute openvswitch-switch服務即可（太坑爹了找了好長時間）