[kolla] neutron-l3-agent namespace NAT table not working?

Radosław Piliszek radoslaw.piliszek at gmail.com
Mon Jan 6 12:33:02 UTC 2020


Folks, this seems to be about C7, not C8, and
"neutron_legacy_iptables" does not apply here.
@Jon - what is the kernel bug you mentioned but never referenced?

-yoctozepto

pon., 6 sty 2020 o 13:13 Jon Masters <jcm at jonmasters.org> napisał(a):
>
> I did specifically check for such a conflict tho before proceeding down the path I went :)
>
> --
> Computer Architect
>
>
> > On Jan 6, 2020, at 03:40, Sean Mooney <smooney at redhat.com> wrote:
> >
> > On Mon, 2020-01-06 at 10:11 +0100, Radosław Piliszek wrote:
> >> If it's RHEL kernel's bug, then Red Hat would likely want to know
> >> about it (if not knowing already).
> >> I have my kolla deployment on c7.7 and I don't encounter this issue,
> >> though there is a pending kernel update so now I'm worried about
> >> applying it...
> > it sound more like a confilct between legacy iptables and the new nftables based replacement.
> > if you mix the two then it will appear as if the rules are installed but only some of the rules will run.
> > so the container images and the host need to be both configured to use the same versions.
> >
> > that said fi you are using centos images on a centos host they should be providing your usnign centos 7 or centos 8 on
> > both. if you try to use centos 7 image on a centos 8 host or centos 8 images on a centos 7 host it would likely have
> > issues due to the fact centos 8 uses a differt iptables implemeantion
> >
> >>
> >> -yoctozepto
> >>
> >> pon., 6 sty 2020 o 03:34 Jon Masters <jcm at jonmasters.org> napisał(a):
> >>>
> >>> There’s no bug ID that I’m aware of. But I’ll go look for one or file one.
> >>>
> >>> --
> >>> Computer Architect
> >>>
> >>>
> >>>> On Jan 5, 2020, at 18:51, Laurent Dumont <laurentfdumont at gmail.com> wrote:
> >>>
> >>> 
> >>> Do you happen to have the bug ID for Centos?
> >>>
> >>> On Sun, Jan 5, 2020 at 2:11 PM Jon Masters <jcm at jonmasters.org> wrote:
> >>>>
> >>>> This turns out to a not well documented bug in the CentOS7.7 kernel that causes exactly nat rules not to run as I
> >>>> was seeing. Oh dear god was this nasty as whatever to find and workaround.
> >>>>
> >>>> --
> >>>> Computer Architect
> >>>>
> >>>>
> >>>>> On Jan 4, 2020, at 10:39, Jon Masters <jcm at jonmasters.org> wrote:
> >>>>>
> >>>>> Excuse top posting on my phone. Also, yes, the namespaces are as described. It’s just that the (correct) nat
> >>>>> rules for the qrouter netns are never running, in spite of the two interfaces existing in that ns and correctly
> >>>>> attached to the vswitch.
> >>>>>
> >>>>> --
> >>>>> Computer Architect
> >>>>>
> >>>>>
> >>>>>>> On Jan 4, 2020, at 07:56, Sean Mooney <smooney at redhat.com> wrote:
> >>>>>>>
> >>>>>>> On Sat, 2020-01-04 at 10:46 +0100, Slawek Kaplonski wrote:
> >>>>>>> Hi,
> >>>>>>>
> >>>>>>> Is this qrouter namespace created with all those rules in container or in the host directly?
> >>>>>>> Do You have qr-xxx and qg-xxx ports from br-int in this qrouter namespace?
> >>>>>>
> >>>>>> in kolla the l3 agent should be running with net=host so the container should be useing the hosts
> >>>>>> root namespace  and it will create network namespaces as needed for the different routers.
> >>>>>>
> >>>>>> the ip table rules should be in the router sub namespaces.
> >>>>>>
> >>>>>>>
> >>>>>>>>> On 4 Jan 2020, at 05:44, Jon Masters <jcm at jonmasters.org> wrote:
> >>>>>>>>
> >>>>>>>> Hi there,
> >>>>>>>>
> >>>>>>>> I've got a weird problem with the neutron-l3-agent container on my deployment. It comes up, sets up the
> >>>>>>>> iptables
> >>>>>>>> rules in the qrouter namespace (and I can see these using "ip netns...") but traffic isn't having DNAT or
> >>>>>>>> SNAT
> >>>>>>>> applied. What's most strange is that manually adding a LOG jump target to the iptables nat PRE/POSTROUTING
> >>>>>>>> chains
> >>>>>>>> (after enabling nf logging sent to the host kernel, confirmed that works) doesn't result in any log
> >>>>>>>> entries. It's as
> >>>>>>>> if the nat table isn't being applied at all for any packets traversing the qrouter namespace. This is
> >>>>>>>> driving me
> >>>>>>>> crazy :)
> >>>>>>>>
> >>>>>>>> Anyone got some quick suggestions? (assume I tried the obvious stuff).
> >>>>>>>>
> >>>>>>>> Jon.
> >>>>>>>>
> >>>>>>>> --
> >>>>>>>> Computer Architect
> >>>>>>>
> >>>>>>> —
> >>>>>>> Slawek Kaplonski
> >>>>>>> Senior software engineer
> >>>>>>> Red Hat
> >>>>>>>
> >>>>>>>
> >>
> >>
> >



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