On Mon, Nov 07, 2016 at 02:12:14PM -0800, Kevin Benton wrote: :Which version of Neutron are you on now? Changing the config options had no :impact on existing networks in Mitaka. After updating the config, only new :networks will be affected. You will need to use an SQL query to update the :existing network MTUs.
Mitaka I understand that old MTU's won't change, but new overlays are gettign created with 1458 MTU despite the configs I thnk should tell it the jumbo underlay size, so I'm probably missing something :) I did discover since neutron is now MTU aware I can simply drop the dhcp-option=26,9000 and (after poking the DB for the existing jumbo networks which had 'Null' MTUs) the old stuff and new stuff work just new stuff has overly restrictive MTU. :This was changed in Newton (https://review.openstack.org/#/c/336805/) but :we couldn't back-port it because of the behavior change. Neat I didn't know support form changing MTU was even planned, but I gues it's here (well not quite *here* but...) -Jon : : :On Fri, Nov 4, 2016 at 10:34 AM, Jonathan Proulx <j...@csail.mit.edu> wrote: : :> Hi All, :> :> :> So long story short how do I get my ml2/ovs GRE tenant network to default :> to :> MTU 9000 in Mitaka - or - get dhcp agents on on netork node to give :> out different MTUs to different networks? :> :> :> Seems between Kilo (my last release) and Mitaka (my current production :> world) Neutron got a lot cleverer about MTUs and teh simple :> workarounds I had to make by jumbo frames go are now causing some :> issues for newly created project networks. :> :> Because I'm setting 'dhcp-option=26,9000' in /etc/neutron/dnsmasq.conf :> everything get an MTU of 9000 inside the guest OS. I only *really* :> care about this for our provider vlans, for project networks I only :> care that they work. :> :> CUrrently when a new project network is created it get an MTU of 1458 :> (1500 less GRE overhead) this is reflected in teh neutron DB and the :> various virtual interfaces on the hypervisor and network node, but :> DHCP configures inside the host to be 9000 and hilarity ensues. :> :> I tried setting DEFAULT/global_physnet_mtu=9134 in neutron.conf and :> ml2/path_mtu=9134 in ml2.ini (which is the actual MTU of L2 links), :> agent/veth_mtu=9134 was previously set. I thought this would result in :> virtualdevices large enough to pass the 9000 traffic but seems to have :> made no difference. :> :> I can kludge around by specifying MTU on network creation (or some :> post facto DB hackery) but this isn't do able through my Horizon UI so :> my users won't do it. :> :> Thanks, :> -Jon :> :> :> _______________________________________________ :> OpenStack-operators mailing list :> OpenStack-operators@lists.openstack.org :> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators :> -- _______________________________________________ OpenStack-operators mailing list OpenStack-operators@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators