[ovs-discuss] newbie discovering ovs
Xavier COUDIN
xavier.coudin at ac-nantes.fr
Thu Jan 20 14:06:40 UTC 2011
Yes, the ovs is running in the host-machine, not in the VMs. This way,
the ovs is running on the same level as the VirtualBox infrastructure.
The bridges and their ports must be created on the host level, and then
should be visible as available interfaces in the hypervisor, and then
should be available for all VMs.
Just like in the page "Vlans" of the documentation-pages on website of
ovs. In this page you can see an image explaining that the VMs (VM1 VM2)
access to the bridge br0 using interfaces called tap0 and tap1. Those
tap0 and tap1 interface must be created on the host level. Then they
appear in the hypervisor, and can be affected by the hypervisor to the VMs.
In my opinion, when those tap0 and tap1 are created, I can tie them to
the br0 , using ovs-vsctl.
So finally an important question probably is : how do I create tap0 and
tap1 ? And what network-configuration should I give to them (probably
dhcp-client) ?
I mean...this is how I understand the global infrastructure...
...But maybe I am making a misunderstanding ??? Does anyone have an
experience about that ?
Another question, completely different:
When managing real physical manageable switches (Nortel, Cisco,...) when
I configure a port as beeing 802.1Q (=multi-vlan ) , I must define a
default vlan-id in this port (default value is usually 1). I could not
see this kind of configuration in the doc of ovs. Is it a
misunderstanding from me, or a missing feature in ovs ?
(note : I don't like to use the word "trunk" about 802.1q beceause in
Netgear switches like FS726T "trunk" means agregate several ports to
increase the bandwidth, so the word "trunk" can have different meaning
depending on the manufacturer)
Henrique Rodrigues a écrit :
> Hi Xavier,
>
> I couldn't understand your setup. The steps I wrote on the previous
> email were supposed to be executed inside the virtual machine that you
> had created using virtualbox. I haven't changed the physical machine
> that is running virtualbox. Maybe what you want to do is completely
> different from what I understood.
>
>
> I will try to explain my actual situation.
>
> I created yesterday a bride br0 within ocs (using ovs-vsctl)
>
> ovs-vsctl list-br gives as result "br0"
>
> ovs-vsctl list-ports br0 gives as result : 6 lines of the
> different ports I created
>
>
> note: I am just sorry that this "ovs-vsctl list-ports br0" gives
> as a result only the name of the ports, and does not give also the
> vlan-id associated to each port. Could this improvement be
> included in the next releases of ovs ?
>
> When I read the docs, I suppose that when creating a port, this
> port is a 802.1q port by default. This port is dedicated to a vlan
> only if I clearly declare it.
>
> I just now added the "libdevplug2" package to my host.
>
> Now I am looking in Virtualbox, and I finally can see a new choice
> appearing:
> In a WM network configuration, if I choose bridge-mode, I can
> see a new choice after eth0 : a new br0 interface has appeared.
> Can this be a result of adding the "libdevplug2" package ?
> But I am "surprised" to see that this new interface does dot
> appear in the ifconfig of the host.
>
> Now I have a new difficulty : br0 is a switch having multiple
> ports. 1 port is supposed to be a 802.1q and the other 5 ports are
> supposed to be in 5 differents vlans. Of course I would like to
> attach my wm to a ports (ie to a vlan) and not to the whole bridge.
>
> Probably I should create a fake-bridge behind 1 vlan-port , and
> see if I can attach the VM to this fake-bridge ?
>
>
>
>
> Le 19/01/2011 12:54, Henrique Rodrigues a écrit :
>
> Hi Xavier,
>
> I'm using the setup openvswitch+vmware for testing my code. I'm
> replying because I had a similar problem in understanding the ovs
> ifaces at the beginning... I'm assuming you've installed ovs
> within
> the virtual box vm. The vm has only two interfaces, one of
> them is the
> vm's physical interface (eth0) and the other is the bridge
> iface that
> would be created by ovs (which can be seen as the "new vm physical
> interface". Ovs will be between these two interfaces, switching
> packets that have been sent through them.
>
> I don't know how the usermode ovs works, but used these steps to
> setup ovs within the vmware vm:
>
> - Compile everything
> - Load the modules
> - Create the ovs bridge (ovs-vsctl add-br)
> - Add eth0 to the bridge (ovs-vsctl add-port) and unset it's
> ip addr
> (set it to 0.0.0.0)
> - Set the bridge iface ip addr to the vm's original ip addr.
> - ping to test.
>
> I hope this helps.
>
> --
> Henrique Rodrigues
>
> On Jan 19, 2011, at 9:12 AM, Xavier
> COUDIN<xavier.coudin at ac-nantes.fr
> <mailto:xavier.coudin at ac-nantes.fr>> wrote:
>
>
>
> Le 19/01/2011 10:06, Justin Pettit a écrit :
>
>
> On Jan 19, 2011, at 12:51 AM, Xavier COUDIN wrote:
>
>
>
>
> There is one thing I cannot understand for the
> moment. Probably I still need to be more familiar
> with the ovs concept.
> I can bind the virtualswitch ( = bridge) to eth0.
> But I would like to bind also the virtual-machines
> (that I created inside VirtualBox) to the bridge
> (or to a fake-bridge).
> So I am expecting a way to create "pseudo" eth
> interface(s) in the host-machine, that could
> appear in the VM-management-console, and that I
> could bind to the VMs (and also to the bridge).
>
>
>
> This is outside the scope of OVS; it's dependent on
> your hypervisor to create those virtual interfaces.
> For example, XenServer will create VIFs in the
> hypervisor (e.g., vif1.0, vif2.0), which are then
> attached to the bridge (e.g., xenbr0). I'm not
> familiar enough with VirtualBox to know what they
> expose. Can you get VirtualBox to work using the
> standard Linux bridge? A "brctl show" will show you
> which interfaces are connected to which bridges. You
> should then be able to replicate that with appropriate
> "ovs-vsctl" commands.
>
> --Justin
>
>
>
>
>
> In bridge mode , the VMs (forget about ovs) can use
> correctly the linux bridge, and reach internet ressources.
>
> Now, when we use ovs (I mean, we try to make it
> work....)......
> the "brctl show" gives no answer : just columns "bridge
> name bridge id STP enabled Interface" , but no answer
> below it.
>
>
>
> --
> Xavier COUDIN - coordinateur informatique
> Lycée Pays-de-Retz, 44210 Pornic, tel 02 40 82 40 19
> poste 167
> Lycée Pro Albert Chassagne, 44560 Paimboeuf, tel 02 40 27
> 51 72
> gsm 06 80 28 40 53
>
>
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>
>
>
>
> --
> Xavier COUDIN - coordinateur informatique
> Lycée Pays-de-Retz, 44210 Pornic, tel 02 40 82 40 19 poste 167
> Lycée Pro Albert Chassagne, 44560 Paimboeuf, tel 02 40 27 51 72
> gsm 06 80 28 40 53
>
>
>
>
> --
> Henrique Rodrigues
>
--
Xavier COUDIN - coordinateur informatique
LP Chassagne, 44680 Paimboeuf, tel. 02 40 27 51 72 poste 717
LG Pays-de-Retz, 44210 Pornic, gsm 06 80 28 40 53
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