On Mon, Sep 10, 2018 at 11:49:06PM +0530, [email protected] wrote: > From: Numan Siddique <[email protected]> > > In the case of OpenStack + OVN, when the VMs are booted on > hypervisors supporting SR-IOV nics, there are no OVS ports > for these VMs. When these VMs sends DHCPv4, DHPCv6 or IPv6 > Router Solicitation requests, the local ovn-controller cannot > reply to these packets. OpenStack Neutron dhcp agent service > needs to be run to serve these requests. > > With the new logical port type - 'external', OVN itself can > handle these requests avoiding the need to deploy any external > services like neutron dhcp agent. > > To make use of this feature, CMS has to > - create a logical port for such VMs > - set the type to 'external' > - set requested-chassis="<chassis-name>" in the options column. > - create a localnet port for the logical switch > - configure the ovn-bridge-mappings option in the OVS db. > > When the ovn-controller running in that 'chassis', detects the > Port_Binding row, it adds the necessary DHCPv4/v6 OF flows. Since > the packet enters the logical switch pipeline via the localnet port, > the inport register (reg14) is set to the tunnel key of localnet > port in the match conditions. > > In case the chassis goes down for some reason, it is the responsibility > of CMS to change the 'requested-chassis' option to some other active > chassis, so that it can serve these requests. > > Signed-off-by: Numan Siddique <[email protected]>
Thank you for working on OVN. This is a specialized use case, so documentation is important. The commit message above gives a lot of context for the feature. The explanation that it's related to SR-IOV and the list of steps are both valuable. I think that it would be helpful to put that information into the OVN documentation, too. It might be appropriate to put something about SR-IOV into ovn-architecture. I don't yet understand the connection to localnet. Can you explain how traffic between the SR-IOV NIC gets to and from the localnet port? Thanks, Ben. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
