Re: openstack neutron ovsdb port creation

Sam Hague

----- Original Message -----
From: "Baudinot Denis Gerold (badi)" <badi@...>
To: "Sam Hague" <shague@...>
Cc: ovsdb-dev@...
Sent: Thursday, July 16, 2015 10:46:18 AM
Subject: AW: [ovsdb-dev] openstack neutron ovsdb port creation

Hi again

I'am trying to understand the relation you mentioned here:

6. odl ovsdb will relate the neutron events to the ovsdb events and build
tunnels and push flows as needed.
I can't figure this out in the case of a neutron port creation. The neutron
port creation gets passed to the PortHandler.

But the NetworkingProvider which is responsible for pushing l2 forwarding
flows onto the bridge is neither notified by a southbound event nor the
mentioned neutron event. The southbound event ADD for port creation is
empty. Only UPDATE seems to pass on the creation to the NetworkingProvider.
Where can I see the relation between the southbound port creation and
neutron port creation?

What confuses me on the side is the fact that the southbound events require
to retrieve a NeutronNetwork from the neutron cache. What happens if the
neutron event happens after the southbound event?
The SouthboundHandler is where the ovs port updates come in. Both the add and update are mapped to a processPortUpdate() since we want to do the same thing for both events. As you saw int he code the PortHandler really doesn't do much. That code is really just there so that the neutron northbound will not reply negatively to neutron rest calls - something is required int he backend to satisfy the request.

So when the ovs port is updated we can then go to program the flows in the handleinterfaceUpdate() method. I don't recall everything that comes in for the port add and update but we can't do anything until the external_ids column is filled with the neutron port iface-id so that we know how to program the flows for the requested network. That is the link between the neutron port and the ovs port.

It always works out that eventually the neutron port stuff comes in followed by a ovs port update. Sometimes there are ovs port add/updates before the neutron port comes in, but in all cases there is a subsequent ovs port update. So eventually you get an ovs update and the neutron cache is there for use.

Thank you *very* much again

Von: Sam Hague [shague@...]
Gesendet: Donnerstag, 9. Juli 2015 14:45
An: Baudinot Denis Gerold (badi)
Cc: ovsdb-dev@...
Betreff: Re: [ovsdb-dev] openstack neutron ovsdb port creation

----- Original Message -----
From: "Baudinot Denis Gerold (badi)" <badi@...>
To: ovsdb-dev@...
Sent: Thursday, July 9, 2015 5:04:23 AM
Subject: [ovsdb-dev] openstack neutron ovsdb port creation


I have read through ovsdb / openstack (helium), but I have issues
identifiying the actual ovs port creation.

Following from PortHandler.neutronPortCreated the only output I found is
programming related. But what I want to see is where ovs ports are created
through ovsdb.

To be more specific I would like to see the part where the ovs ports and
interfaces are created by ovsdb, which are attached to tap devices to
connectivity to VM instances in an openstack environment.

the ovsdb project will only add patch and tunnel ports as needed. The VM
ports are added via the libvirt agent on the openstack compute nodes. The
flow is like this:

Network creation:
1. User creates a network via openstack
2. neutron agents add ports to bridges for routers and dhcp namespaces -
these are the tap ports you mention above
3. neutron and ovsdb port updates go to odl
4. neutron events passed to odl ovsdb project - not much happens here
5. ovsdb port events go directly to the odl ovsdb
6. odl ovsdb will relate the neutron events to the ovsdb events and build
tunnels and push flows as needed.

VM Creation:
1. User creates VM's via openstack
2. nova calls libvirt to create VM
3. libvirt calls will allocate VM ports and add them to the br-int - these
are the tap ports you mention above
4. Same as 3-6 above.

I assume that the opendaylight.neutron bundle itself is only responsible
the northbound API to the neutron ml2 plugin and opendaylight.ovsdb does
the work regarding to ovs.
yes, odl.neutron receives the incoming neutron rest APIs. And then
effectively passes them through to odl.ovsdb to do the work.

Thank you

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