DPDK on Cisco UCS - OVS user Bridge report "cannot open datapath local port br-provider-vnic7 (Device or resource busy)"

Issue

• DPDK is configured the same way for 2 vNIC on the compute nic-config template.

• Each vNIC has its own ovs user bridge. There is no bond since HA is manage at UCS Manager profile.

• Behavior in the resulting configurtion is different for br-provider-vnic6 and br-provider-vnic7.

• The following nic templates are being used:

             - type: ovs_user_bridge
                name: br-provider-vnic6
                use_dhcp: false
                mtu: 9000
                members:
                  - type: ovs_dpdk_port
                    name: dpdk0
                    mtu: 9000
                    members:
                      - type: interface
                        name: nic6
              - type: ovs_user_bridge
                name: br-provider-vnic7
                use_dhcp: false
                mtu: 9000
                members:
                  - type: ovs_dpdk_port
                    name: dpdk1
                    mtu: 9000
                    members:
                      - type: interface
                        name: nic7

• ovs-vsctl show reports the following error:

[root@overcloud-compute-0 openvswitch]# ovs-vsctl show
d90308e9-d3f3-4de1-b9b5-66543bd2afe9
    Manager "ptcp:6640:127.0.0.1"
        is_connected: true
    Bridge "br-provider-vnic7"
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "phy-br-pr9fbad8"
            Interface "phy-br-pr9fbad8"
                type: patch
                options: {peer="int-br-pr9fbad8"}
        Port "dpdk1"
            Interface "dpdk1"
                type: dpdk
                options: {dpdk-devargs="0000:11:00.0"}
        Port "br-provider-vnic7"
            Interface "br-provider-vnic7"
                type: internal
                error: "could not open network device br-provider-vnic7 (Device or resource busy)"
    Bridge br-int
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "int-br-pr62c3e5"
            Interface "int-br-pr62c3e5"
                type: patch
                options: {peer="phy-br-pr62c3e5"}
        Port "int-br-pr9fbad8"
            Interface "int-br-pr9fbad8"
                type: patch
                options: {peer="phy-br-pr9fbad8"}
        Port patch-tun
            Interface patch-tun
                type: patch
                options: {peer=patch-int}
        Port br-int
            Interface br-int
                type: internal
    Bridge br-tun
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "vxlan-0a010013"
            Interface "vxlan-0a010013"
                type: vxlan
                options: {df_default="true", in_key=flow, local_ip="10.10.10.10", out_key=flow, remote_ip="10.1.0.19"}
        Port "vxlan-0a010011"
            Interface "vxlan-0a010011"
                type: vxlan
                options: {df_default="true", in_key=flow, local_ip="10.10.10.10", out_key=flow, remote_ip="10.10.10.11"}
        Port "vxlan-0a010012"
            Interface "vxlan-0a010012"
                type: vxlan
                options: {df_default="true", in_key=flow, local_ip="10.10.10.10", out_key=flow, remote_ip="10.10.10.12"}
        Port "vxlan-0a010017"
            Interface "vxlan-0a010017"
                type: vxlan
                options: {df_default="true", in_key=flow, local_ip="10.10.10.10", out_key=flow, remote_ip="10.10.10.13"}
        Port br-tun
            Interface br-tun
                type: internal
        Port patch-int
            Interface patch-int
                type: patch
                options: {peer=patch-tun}
        Port "vxlan-0a01001a"
            Interface "vxlan-0a01001a"
                type: vxlan
                options: {df_default="true", in_key=flow, local_ip="10.10.10.10", out_key=flow, remote_ip="10.10.10.14"}
    Bridge "br-provider-vnic6"
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "br-provider-vnic6"
            Interface "br-provider-vnic6"
                type: internal
        Port "dpdk0"
            Interface "dpdk0"
                type: dpdk
                options: {dpdk-devargs="0000:10:00.0"}
        Port "phy-br-pr62c3e5"
            Interface "phy-br-pr62c3e5"
                type: patch
                options: {peer="int-br-pr62c3e5"}
    ovs_version: "2.9.0"

• /var/log/openvswitch/ovs-vswitchd.log shows errors similar to these:

019-10-04T09:50:27.018Z|00090|netdev_linux|WARN|br-provider-vnic7: creating tap device failed: Device or resource busy
2019-10-04T09:50:27.018Z|00091|bridge|WARN|could not open network device br-provider-vnic7 (Device or resource busy)
2019-10-04T09:50:27.018Z|00092|bridge|INFO|bridge br-provider-vnic7: using datapath ID 00008a55a43c1d4c
2019-10-04T09:50:27.018Z|00093|connmgr|INFO|br-provider-vnic7: added service controller "punix:/var/run/openvswitch/br-provider-vnic7.mgmt"