[ovs-discuss] I can't manage to use more than one port on the vswitch

Scott Lowe scott.lowe at scottlowe.org
Thu Sep 28 15:00:06 UTC 2017


> On Sep 28, 2017, at 8:50 AM, O Alabeatrix <oalabeatrix at gmail.com> wrote:
> 
> Hi
> 
> I’m a network admin starting to learn Open vSwitch. I don’t manage to make it functionning.
> I’m using Debian 9 with three physical interfaces:
> . enp0s3: management interfaces
> . enp0s8: physical interface on vswitch0
> . enp0s9: physical interface on vswitch1
> 
> vswitch0 (LOCALE) IP: 192.168.1.200
> 
> Theorically, as there is an IP on vswitch0, it shouldn’t matter wether it’s enp0s8 or enp0s9 that is plugged into the 192.168.1.0/24 network.
> Alas, it’s only when enp0s9 is used that the ping to the outter physical IP succeed.
> An both in default L2 and OpenFlow3 mode.
> 
> Here are the config and status files:
> 
> Debian9 config:
> 
> sudo apt-get update
> sudo apt-get dist-upgrade
> sudo apt-get install openvswitch-switch openvswitch-common
> sudo ovs-vsctl add-br vswitch0
> sudo ip link set vswitch0 up
> sudo ip addr flush dev enp0s8
> sudo ip addr flush dev enp0s9
> sudo ovs-vsctl add-port vswitch0 enp0s8
> sudo ovs-vsctl add-port vswitch0 enp0s9
> sudo ip link set enp0s8 up
> sudo ip link set enp0s9 up
> sudo ip addr add 192.168.1.200/24 dev vswitch0
> 
> Normal default L2 Test:
> 
> ping -c 3 192.168.1.1 ---> Fails, unless I swap the interfaces used
> 
> Status:
> 
> sudo ovs-vsctl show
> bf88303a-48cb-48b6-bd07-af1b8eaaca89
>     Bridge "vswitch0"
>         Port "enp0s9"
>             Interface "enp0s9"
>         Port "vswitch0"
>             Interface "vswitch0"
>                 type: internal
>         Port "enp0s8"
>             Interface "enp0s8"
>     ovs_version: "2.6.2"
> 
> --
> sudo ovs-ofctl show vswitch0
> OFPT_FEATURES_REPLY (xid=0x2): dpid:0000080027c5c636
> n_tables:254, n_buffers:256
> capabilities: FLOW_STATS TABLE_STATS PORT_STATS QUEUE_STATS ARP_MATCH_IP
> actions: output enqueue set_vlan_vid set_vlan_pcp strip_vlan mod_dl_src mod_dl_dst mod_nw_src mod_nw_dst mod_nw_tos mod_tp_src mod_tp_dst
> 1(enp0s8): addr:08:00:27:f4:a5:b9
>      config:     0
>      state:      0
>      current:    1GB-FD COPPER AUTO_NEG
>      advertised: 10MB-HD 10MB-FD 100MB-HD 100MB-FD 1GB-FD COPPER AUTO_NEG
>      supported:  10MB-HD 10MB-FD 100MB-HD 100MB-FD 1GB-FD COPPER AUTO_NEG
>      speed: 1000 Mbps now, 1000 Mbps max
> 2(enp0s9): addr:08:00:27:c5:c6:36
>      config:     0
>      state:      0
>      current:    1GB-FD COPPER AUTO_NEG
>      advertised: 10MB-HD 10MB-FD 100MB-HD 100MB-FD 1GB-FD COPPER AUTO_NEG
>      supported:  10MB-HD 10MB-FD 100MB-HD 100MB-FD 1GB-FD COPPER AUTO_NEG
>      speed: 1000 Mbps now, 1000 Mbps max
> LOCAL(vswitch0): addr:08:00:27:c5:c6:36
>      config:     0
>      state:      0
>      speed: 0 Mbps now, 0 Mbps max
> OFPT_GET_CONFIG_REPLY (xid=0x4): frags=normal miss_send_len=0
> --
> sudo ovs-ofctl dump-flows vswitch0
> NXST_FLOW reply (xid=0x4):
> cookie=0x0, duration=686.922s, table=0, n_packets=224, n_bytes=28746, idle_age=1, priority=0 actions=NORMAL
> ----
> 
> OpenFlow3 mode and tests:
> 
> sudo ovs-vsctl set bridge vswitch0 protocols=OpenFlow13
> sudo ovs-ofctl -O Openflow13 dump-flows vswitch0
> 
> OFPST_FLOW reply (OF1.3) (xid=0x2):
> cookie=0x0, duration=1334.814s, table=0, n_packets=398, n_bytes=66282, priority=0 actions=NORMAL
> 
> ping 192.168.1.1 –> Fail ( functions if I swap the interfaces cables)
> 
> I just can’t figure out what is going wrong here, even after compairing the status files ( ip link show, ip addr show).
> thanks for any help <wlEmoticon-smile[1].png>


In this instance, I think it's appropriate to ask about the upstream switch configuration. I don't see anything immediately odd about your configuration, so we'll need to determine how OVS is interacting with the upstream physical switch (things like VLANs, tagging, etc.).

Also, since you have 2 NICs added to the OVS bridge and don't appear to be connected to an OpenFlow controller, you'll need to address bridging loops and Spanning Tree. Specifically, you'll want to either a) place the physical interfaces in different broadcast domains, or b) use some form of link aggregation.

--
Scott

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