ovn学习-2-ovsdb

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ovsdb协议

ovn-arch

client库

自带 C 和 Python的。其他开源的库有

  • golang
    https://github.com/socketplane/libovsdb/blob/master/example/play_with_ovs.go
    https://github.com/contiv/ofnet/blob/master/ovsdbDriver/ovsdbDriver.go
  • python
    ovsdbapp

以下是一个ovsdbapp使用的例子，

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from ovsdbapp.backend.ovs_idl import connection
from ovsdbapp import constants
from ovsdbapp.schema.open_vswitch import impl_idl
ovsdb_connection = connection.Connection(
    idl=connection.OvsdbIdl.from_server(
        'unix:/var/run/openvswitch/db.sock', 'Open_vSwitch'),
    timeout=constants.DEFAULT_TIMEOUT)
api = impl_idl.OvsdbIdl(ovsdb_connection)
result = api.br_exists("br0").execute(check_error=True)
print result
result = api.del_br("br1").execute(check_error=True)
print result

协议交互举例

ovs-vsctl操作的是ovs db。ovs-vswitchd有monitor ovs db，ovs db的变更都会发到ovs-vswitchd。ovs-vsctl和ovs-vswitchd都是通过ovsdb-server进程（unix socket或者是tcp连接）去watch或者update db的。

以ovs-vsctl add-port br0 abc -- set interface abc type=internal为例，
ovs-vsctl会在ovsdb的Port表和Interface表增加一行数据，ovs-vswitchd收到通知后，会创建接口，并且把ofport，mtu，mac，link_state等信息写入Interface表里。写入是否成功呢，还是靠的监控通知机制。

ovs-vsctl -v可以打印出ovs-vsctl和ovsdb-server详细的json rpc交互过程。

ovsdb-client monitor tcp:127.0.0.1:6640 Interface name,ofport,external_ids --format=json这个命令可以watch某些表某些字段的变更通知：

1. 初始时会把所有的内容返回来。
2. 以后只会返回变化的。
3. 注意，返回的action里有initial，delete, new不是实际协议的内容，这是处理过了的。协议里只有old和new。见rfc里的4.1.6里的解释。

ovs-vswitchd消息处理过程如下，

  • 收到update通知消息，
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[null, {
    "Port": {
        "5943a115-162f-484f-8e45-5cbf9cd112c5": {
            "new": {
                "name": "abc",
                "statistics": ["map", []],
                "vlan_mode": ["set", []],
                "qos": ["set", []],
                "trunks": ["set", []],
                "mac": ["set", []],
                "status": ["map", []],
                "interfaces": ["uuid", "9fb84aa6-ac6e-4575-b4e7-0cc87c755195"],
                "bond_downdelay": 0,
                "bond_mode": ["set", []],
                "bond_updelay": 0,
                "other_config": ["map", []],
                "bond_fake_iface": false,
                "tag": ["set", []],
                "fake_bridge": false,
                "lacp": ["set", []]
            }
        }
    },
    "Bridge": {
        "3d081a41-f691-41a6-a469-d0a0100fbf8c": {
            "old": {
                "ports": ["set", [
                    ["uuid", "10c55211-94b2-4bc7-aefb-e524c3f1f7eb"],
                    ["uuid", "421029b9-2467-4946-bece-1e408524a2f9"]
                ]]
            },
            "new": {
                "name": "br0",
                "flood_vlans": ["set", []],
                "netflow": ["set", []],
                "mirrors": ["set", []],
                "status": ["map", []],
                "datapath_id": "0000421a083da641",
                "controller": ["set", []],
                "ipfix": ["set", []],
                "protocols": ["set", []],
                "fail_mode": ["set", []],
                "ports": ["set", [
                    ["uuid", "10c55211-94b2-4bc7-aefb-e524c3f1f7eb"],
                    ["uuid", "421029b9-2467-4946-bece-1e408524a2f9"],
                    ["uuid", "5943a115-162f-484f-8e45-5cbf9cd112c5"]
                ]],
                "other_config": ["map", []],
                "flow_tables": ["map", []],
                "sflow": ["set", []],
                "datapath_type": "",
                "stp_enable": false
            }
        }
    },
    "Interface": {
        "9fb84aa6-ac6e-4575-b4e7-0cc87c755195": {
            "new": {
                "name": "abc",
                "options": ["map", []],
                "mtu": ["set", []],
                "link_speed": ["set", []],
                "statistics": ["map", []],
                "mac_in_use": ["set", []],
                "type": "internal",
                "cfm_remote_opstate": ["set", []],
                "ingress_policing_rate": 0,
                "status": ["map", []],
                "mac": ["set", []],
                "ofport": ["set", []],
                "ifindex": ["set", []],
                "cfm_fault_status": ["set", []],
                "duplex": ["set", []],
                "lacp_current": ["set", []],
                "cfm_fault": ["set", []],
                "bfd_status": ["map", []],
                "link_state": ["set", []],
                "admin_state": ["set", []],
                "other_config": ["map", []],
                "cfm_remote_mpids": ["set", []],
                "ingress_policing_burst": 0,
                "ofport_request": ["set", []],
                "bfd": ["map", []],
                "cfm_mpid": ["set", []],
                "cfm_flap_count": ["set", []],
                "link_resets": ["set", []],
                "cfm_health": ["set", []]
            }
        }
    },
    "Open_vSwitch": {
        "099e083f-aa09-4dd1-95d2-d0b4857eb3b9": {
            "old": {
                "next_cfg": 70
            },
            "new": {
                "statistics": ["map", []],
                "manager_options": ["uuid", "28542e8a-9886-4282-8b43-afb5b80c0cc5"],
                "bridges": ["set", [
                    ["uuid", "3d081a41-f691-41a6-a469-d0a0100fbf8c"],
                    ["uuid", "558db8c8-bc39-4781-a441-f58e7dc6a951"]
                ]],
                "other_config": ["map", []],
                "ssl": ["set", []],
                "next_cfg": 71,
                "cur_cfg": 70
            }
        }
    }
}]
  • 创建接口，bridge br0: added interface abc on port 10
  • 更新ovsdb，

发送transact请求1，

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["Open_vSwitch", {
    "lock": "ovs_vswitchd",
    "op": "assert"
}, {
    "row": {
        "ofport": 10,
        "statistics": ["map", [
            ["collisions", 0],
            ["rx_bytes", 0],
            ["rx_crc_err", 0],
            ["rx_dropped", 0],
            ["rx_errors", 0],
            ["rx_frame_err", 0],
            ["rx_over_err", 0],
            ["rx_packets", 0],
            ["tx_bytes", 0],
            ["tx_dropped", 0],
            ["tx_errors", 0],
            ["tx_packets", 0]
        ]]
    },
    "table": "Interface",
    "where": [
        ["_uuid", "==", ["uuid", "9fb84aa6-ac6e-4575-b4e7-0cc87c755195"]]
    ],
    "op": "update"
}, {
    "row": {
        "cur_cfg": 71
    },
    "table": "Open_vSwitch",
    "where": [
        ["_uuid", "==", ["uuid", "099e083f-aa09-4dd1-95d2-d0b4857eb3b9"]]
    ],
    "op": "update"
}]

请求2，

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["Open_vSwitch", {
    "lock": "ovs_vswitchd",
    "op": "assert"
}, {
    "row": {
        "status": ["map", [
            ["driver_name", "openvswitch"]
        ]],
        "mtu": 1500,
        "mac_in_use": "6e:2b:1b:5e:23:8f",
        "link_state": "down",
        "link_resets": 0,
        "admin_state": "down",
        "ifindex": 22
    },
    "table": "Interface",
    "where": [
        ["_uuid", "==", ["uuid", "9fb84aa6-ac6e-4575-b4e7-0cc87c755195"]]
    ],
    "op": "update"
}]
  • 收到update通知消息（因为上面的update transact），

update通知消息1，

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[null, {
    "Interface": {
        "9fb84aa6-ac6e-4575-b4e7-0cc87c755195": {
            "old": {
                "statistics": ["map", []],
                "ofport": ["set", []]
            },
            "new": {
                "name": "abc",
                "options": ["map", []],
                "mtu": ["set", []],
                "link_speed": ["set", []],
                "statistics": ["map", [
                    ["collisions", 0],
                    ["rx_bytes", 0],
                    ["rx_crc_err", 0],
                    ["rx_dropped", 0],
                    ["rx_errors", 0],
                    ["rx_frame_err", 0],
                    ["rx_over_err", 0],
                    ["rx_packets", 0],
                    ["tx_bytes", 0],
                    ["tx_dropped", 0],
                    ["tx_errors", 0],
                    ["tx_packets", 0]
                ]],
                "mac_in_use": ["set", []],
                "type": "internal",
                "cfm_remote_opstate": ["set", []],
                "ingress_policing_rate": 0,
                "status": ["map", []],
                "mac": ["set", []],
                "ofport": 10,
                "ifindex": ["set", []],
                "cfm_fault_status": ["set", []],
                "duplex": ["set", []],
                "lacp_current": ["set", []],
                "cfm_fault": ["set", []],
                "bfd_status": ["map", []],
                "link_state": ["set", []],
                "admin_state": ["set", []],
                "other_config": ["map", []],
                "cfm_remote_mpids": ["set", []],
                "ingress_policing_burst": 0,
                "ofport_request": ["set", []],
                "bfd": ["map", []],
                "cfm_mpid": ["set", []],
                "cfm_flap_count": ["set", []],
                "link_resets": ["set", []],
                "cfm_health": ["set", []]
            }
        }
    },
    "Open_vSwitch": {
        "099e083f-aa09-4dd1-95d2-d0b4857eb3b9": {
            "old": {
                "cur_cfg": 70
            },
            "new": {
                "statistics": ["map", []],
                "manager_options": ["uuid", "28542e8a-9886-4282-8b43-afb5b80c0cc5"],
                "bridges": ["set", [
                    ["uuid", "3d081a41-f691-41a6-a469-d0a0100fbf8c"],
                    ["uuid", "558db8c8-bc39-4781-a441-f58e7dc6a951"]
                ]],
                "other_config": ["map", []],
                "ssl": ["set", []],
                "next_cfg": 71,
                "cur_cfg": 71
            }
        }
    }
}]

update通知消息2，

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[null, {
    "Interface": {
        "9fb84aa6-ac6e-4575-b4e7-0cc87c755195": {
            "old": {
                "status": ["map", []],
                "mtu": ["set", []],
                "mac_in_use": ["set", []],
                "link_state": ["set", []],
                "admin_state": ["set", []],
                "link_resets": ["set", []],
                "ifindex": ["set", []]
            },
            "new": {
                "name": "abc",
                "options": ["map", []],
                "mtu": 1500,
                "link_speed": ["set", []],
                "statistics": ["map", [
                    ["collisions", 0],
                    ["rx_bytes", 0],
                    ["rx_crc_err", 0],
                    ["rx_dropped", 0],
                    ["rx_errors", 0],
                    ["rx_frame_err", 0],
                    ["rx_over_err", 0],
                    ["rx_packets", 0],
                    ["tx_bytes", 0],
                    ["tx_dropped", 0],
                    ["tx_errors", 0],
                    ["tx_packets", 0]
                ]],
                "mac_in_use": "6e:2b:1b:5e:23:8f",
                "type": "internal",
                "cfm_remote_opstate": ["set", []],
                "ingress_policing_rate": 0,
                "status": ["map", [
                    ["driver_name", "openvswitch"]
                ]],
                "mac": ["set", []],
                "ofport": 10,
                "ifindex": 22,
                "cfm_fault_status": ["set", []],
                "duplex": ["set", []],
                "lacp_current": ["set", []],
                "cfm_fault": ["set", []],
                "bfd_status": ["map", []],
                "link_state": "down",
                "admin_state": "down",
                "other_config": ["map", []],
                "cfm_remote_mpids": ["set", []],
                "ingress_policing_burst": 0,
                "ofport_request": ["set", []],
                "bfd": ["map", []],
                "cfm_mpid": ["set", []],
                "cfm_flap_count": ["set", []],
                "link_resets": 0,
                "cfm_health": ["set", []]
            }
        }
    }
}]