On Tue, Nov 20, 2018 at 1:37 AM Gregory Smith <[email protected]> wrote:
> Numan Siddique wrote: > > On Fri, Nov 16, 2018 at 11:03 PM Gregory Smith <[email protected]> > wrote: > > > > > See RFC 2131, section 4.3.2. When handling a DHCPREQUEST message, the > > > server should validate that the client's requested IP matches the > > > offered IP. > > > > When we added the native DHCP support in OVN, we primarily had > > OpenStack in mind and wanted to get rid of neutron dhcp agent service. > > In the case of OpenStack, when a port is created, the IP address is > > assigned to it by the Neutron IPAM. This IP address will most likely > > will remain the same for the port. So we added a simple native DHCP > > implementation. > > > > I want to understand the use case for this requirement. Can you please > > give more details. Does a CMS update the address of a logical port at > > a later point of time ? > > We’ve been cloning windows VMs, and we’ve observed that the clone > sometimes requests its parent’s IP address during boot, despite having > been assigned a new adapter MAC address. The Windows DHCP client gets > confused when it gets a DHCPACK for a different address, and reacts by > repeating its original DHCPREQUEST. After a few retries, it gives up and > uses the old address. It never sends a DHCPDISCOVER. By contrast, when > the Windows DHCP client recieves a DHCPNAK, it immediately sends a > DHCPDISCOVER to discover its new address. > Thanks for sharing this. > > Regarding OpenStack: I understand that it is not common to change a > Neutron port's IP address assignment, but this is certainly a supported > workflow. Are there any other parts of OVN that assume the port's IP > address assignment is immutable? > No. CMS can change the port's IP addresses at any point and OVN should handle it. I was just curious to know the use case. I will take a look at the patch. Thanks Numan > > Greg > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
