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Many thanks for your explanation, Sean.
Ignazio

Il Ven 12 Mar 2021, 23:44 Sean Mooney <smooney at redhat.com> ha scritto:

> On Fri, 2021-03-12 at 08:13 +0000, Tobias Urdin wrote:
> > Hello,
> >
> > If it's the same as us, then yes, the issue occurs on Train and is not
> completely solved yet.
> there is a downstream bug trackker for this
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1917675
>
> its fixed by a combination of 3 enturon patches and i think 1 nova one
>
> https://review.opendev.org/c/openstack/neutron/+/766277/
> https://review.opendev.org/c/openstack/neutron/+/753314/
> https://review.opendev.org/c/openstack/neutron/+/640258/
>
> and
> https://review.opendev.org/c/openstack/nova/+/770745
>
> the first tree neutron patches would fix the evauate case but break live
> migration
> the nova patch means live migration will work too although to fully fix
> the related
> live migration packet loss issues you need
>
> https://review.opendev.org/c/openstack/nova/+/747454/4
> https://review.opendev.org/c/openstack/nova/+/742180/12
> to fix live migration with network abckend that dont suppor tmultiple port
> binding
> and
> https://review.opendev.org/c/openstack/nova/+/602432 (the only one not
> merged yet.)
> for live migrateon with ovs and hybridg plug=false (e.g. ovs firewall
> driver, noop or ovn instead of ml2/ovs.
>
> multiple port binding was not actully the reason for this there was a race
> in neutorn itslef that would have haapend
> even without multiple port binding between the dhcp agent and l2 agent.
>
> some of those patches have been backported already and all shoudl
> eventually make ti to train the could be brought to stine potentially
> if peopel are open to backport/review them.
>
>
> >
> >
> > Best regards
> >
> > ________________________________
> > From: Ignazio Cassano <ignaziocassano at gmail.com>
> > Sent: Friday, March 12, 2021 7:43:22 AM
> > To: Tobias Urdin
> > Cc: openstack-discuss
> > Subject: Re: [stein][neutron] gratuitous arp
> >
> > Hello Tobias, the result is the same as your.
> > I do not know what happens in depth to evaluate if the behavior is the
> same.
> > I solved on stein with patch suggested by Sean : force_legacy_port_bind
> workaround.
> > So I am asking if the problem exists also on train.
> > Ignazio
> >
> > Il Gio 11 Mar 2021, 19:27 Tobias Urdin <tobias.urdin at binero.com<mailto:
> tobias.urdin at binero.com>> ha scritto:
> >
> > Hello,
> >
> >
> > Not sure if you are having the same issue as us, but we are following
> https://bugs.launchpad.net/neutron/+bug/1901707 but
> >
> > are patching it with something similar to
> https://review.opendev.org/c/openstack/nova/+/741529 to workaround the
> issue until it's completely solved.
> >
> >
> > Best regards
> >
> > ________________________________
> > From: Ignazio Cassano <ignaziocassano at gmail.com<mailto:
> ignaziocassano at gmail.com>>
> > Sent: Wednesday, March 10, 2021 7:57:21 AM
> > To: Sean Mooney
> > Cc: openstack-discuss; Slawek Kaplonski
> > Subject: Re: [stein][neutron] gratuitous arp
> >
> > Hello All,
> > please, are there news about bug 1815989 ?
> > On stein I modified code as suggested in the patches.
> > I am worried when I will upgrade to train: wil this bug persist ?
> > On which openstack version this bug is resolved ?
> > Ignazio
> >
> >
> >
> > Il giorno mer 18 nov 2020 alle ore 07:16 Ignazio Cassano <
> ignaziocassano at gmail.com<mailto:ignaziocassano at gmail.com>> ha scritto:
> > Hello, I tried to update to last stein packages on yum and seems this
> bug still exists.
> > Before the yum update I patched some files as suggested and and ping to
> vm worked fine.
> > After yum update the issue returns.
> > Please, let me know If I must patch files by hand or some new parameters
> in configuration can solve and/or the issue is solved in newer openstack
> versions.
> > Thanks
> > Ignazio
> >
> >
> > Il Mer 29 Apr 2020, 19:49 Sean Mooney <smooney at redhat.com<mailto:
> smooney at redhat.com>> ha scritto:
> > On Wed, 2020-04-29 at 17:10 +0200, Ignazio Cassano wrote:
> > > Many thanks.
> > > Please keep in touch.
> > here are the two patches.
> > the first https://review.opendev.org/#/c/724386/ is the actual change
> to add the new config opition
> > this needs a release note and some tests but it shoudl be functional
> hence the [WIP]
> > i have not enable the workaround in any job in this patch so the ci run
> will assert this does not break
> > anything in the default case
> >
> > the second patch is https://review.opendev.org/#/c/724387/ which
> enables the workaround in the multi node ci jobs
> > and is testing that live migration exctra works when the workaround is
> enabled.
> >
> > this should work as it is what we expect to happen if you are using a
> moderne nova with an old neutron.
> > its is marked [DNM] as i dont intend that patch to merge but if the
> workaround is useful we migth consider enableing
> > it for one of the jobs to get ci coverage but not all of the jobs.
> >
> > i have not had time to deploy a 2 node env today but ill try and test
> this locally tomorow.
> >
> >
> >
> > > Ignazio
> > >
> > > Il giorno mer 29 apr 2020 alle ore 16:55 Sean Mooney <
> smooney at redhat.com<mailto:smooney at redhat.com>>
> > > ha scritto:
> > >
> > > > so bing pragmatic i think the simplest path forward given my other
> patches
> > > > have not laned
> > > > in almost 2 years is to quickly add a workaround config option to
> disable
> > > > mulitple port bindign
> > > > which we can backport and then we can try and work on the actual fix
> after.
> > > > acording to https://bugs.launchpad.net/neutron/+bug/1815989 that
> shoudl
> > > > serve as a workaround
> > > > for thos that hav this issue but its a regression in functionality.
> > > >
> > > > i can create a patch that will do that  in an hour or so and submit a
> > > > followup DNM patch to enabel the
> > > > workaound in one of the gate jobs that tests live migration.
> > > > i have a meeting in 10  mins and need to finish the pacht im
> currently
> > > > updating but ill submit a poc once that is done.
> > > >
> > > > im not sure if i will be able to spend time on the actul fix which i
> > > > proposed last year but ill see what i can do.
> > > >
> > > >
> > > > On Wed, 2020-04-29 at 16:37 +0200, Ignazio Cassano wrote:
> > > > > PS
> > > > >  I have testing environment on queens,rocky and stein and I can
> make test
> > > > > as you need.
> > > > > Ignazio
> > > > >
> > > > > Il giorno mer 29 apr 2020 alle ore 16:19 Ignazio Cassano <
> > > > > ignaziocassano at gmail.com<mailto:ignaziocassano at gmail.com>> ha
> scritto:
> > > > >
> > > > > > Hello Sean,
> > > > > > the following is the configuration on my compute nodes:
> > > > > > [root at podiscsivc-kvm01 network-scripts]# rpm -qa|grep libvirt
> > > > > > libvirt-daemon-driver-storage-iscsi-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-kvm-4.5.0-33.el7.x86_64
> > > > > > libvirt-libs-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-network-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-nodedev-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-gluster-4.5.0-33.el7.x86_64
> > > > > > libvirt-client-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-core-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-logical-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-secret-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-nwfilter-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-scsi-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-rbd-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-config-nwfilter-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-disk-4.5.0-33.el7.x86_64
> > > > > > libvirt-bash-completion-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-qemu-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-4.5.0-33.el7.x86_64
> > > > > > libvirt-python-4.5.0-1.el7.x86_64
> > > > > > libvirt-daemon-driver-interface-4.5.0-33.el7.x86_64
> > > > > > libvirt-daemon-driver-storage-mpath-4.5.0-33.el7.x86_64
> > > > > > [root at podiscsivc-kvm01 network-scripts]# rpm -qa|grep qemu
> > > > > > qemu-kvm-common-ev-2.12.0-44.1.el7_8.1.x86_64
> > > > > > qemu-kvm-ev-2.12.0-44.1.el7_8.1.x86_64
> > > > > > libvirt-daemon-driver-qemu-4.5.0-33.el7.x86_64
> > > > > > centos-release-qemu-ev-1.0-4.el7.centos.noarch
> > > > > > ipxe-roms-qemu-20180825-2.git133f4c.el7.noarch
> > > > > > qemu-img-ev-2.12.0-44.1.el7_8.1.x86_64
> > > > > >
> > > > > >
> > > > > > As far as firewall driver
> > > >
> > > > /etc/neutron/plugins/ml2/openvswitch_agent.ini:
> > > > > >
> > > > > > firewall_driver = iptables_hybrid
> > > > > >
> > > > > > I have same libvirt/qemu version on queens, on rocky and on stein
> > > >
> > > > testing
> > > > > > environment and the
> > > > > > same firewall driver.
> > > > > > Live migration on provider network on queens works fine.
> > > > > > It does not work fine on rocky and stein (vm lost connection
> after it
> > > >
> > > > is
> > > > > > migrated and start to respond only when the vm send a network
> packet ,
> > > >
> > > > for
> > > > > > example when chrony pools the time server).
> > > > > >
> > > > > > Ignazio
> > > > > >
> > > > > >
> > > > > >
> > > > > > Il giorno mer 29 apr 2020 alle ore 14:36 Sean Mooney <
> > > >
> > > > smooney at redhat.com<mailto:smooney at redhat.com>>
> > > > > > ha scritto:
> > > > > >
> > > > > > > On Wed, 2020-04-29 at 10:39 +0200, Ignazio Cassano wrote:
> > > > > > > > Hello, some updated about this issue.
> > > > > > > > I read someone has got same issue as reported here:
> > > > > > > >
> > > > > > > > https://bugs.launchpad.net/neutron/+bug/1866139
> > > > > > > >
> > > > > > > > If you read the discussion, someone tells that the garp must
> be
> > > >
> > > > sent by
> > > > > > > > qemu during live miration.
> > > > > > > > If this is true, this means on rocky/stein the qemu/libvirt
> are
> > > >
> > > > bugged.
> > > > > > >
> > > > > > > it is not correct.
> > > > > > > qemu/libvir thas alsway used RARP which predates GARP to serve
> as
> > > >
> > > > its mac
> > > > > > > learning frames
> > > > > > > instead
> > > >
> > > > https://en.wikipedia.org/wiki/Reverse_Address_Resolution_Protocol
> > > > > > >
> https://lists.gnu.org/archive/html/qemu-devel/2009-10/msg01457.html
> > > > > > > however it looks like this was broken in 2016 in qemu 2.6.0
> > > > > > >
> https://lists.gnu.org/archive/html/qemu-devel/2016-07/msg04645.html
> > > > > > > but was fixed by
> > > > > > >
> > > >
> > > >
> https://github.com/qemu/qemu/commit/ca1ee3d6b546e841a1b9db413eb8fa09f13a061b
> > > > > > > can you confirm you are not using the broken 2.6.0 release and
> are
> > > >
> > > > using
> > > > > > > 2.7 or newer or 2.4 and older.
> > > > > > >
> > > > > > >
> > > > > > > > So I tried to use stein and rocky with the same version of
> > > >
> > > > libvirt/qemu
> > > > > > > > packages I installed on queens (I updated compute and
> controllers
> > > >
> > > > node
> > > > > > >
> > > > > > > on
> > > > > > > > queens for obtaining same libvirt/qemu version deployed on
> rocky
> > > >
> > > > and
> > > > > > >
> > > > > > > stein).
> > > > > > > >
> > > > > > > > On queens live migration on provider network continues to
> work
> > > >
> > > > fine.
> > > > > > > > On rocky and stein not, so I think the issue is related to
> > > >
> > > > openstack
> > > > > > > > components .
> > > > > > >
> > > > > > > on queens we have only a singel prot binding and nova blindly
> assumes
> > > > > > > that the port binding details wont
> > > > > > > change when it does a live migration and does not update the
> xml for
> > > >
> > > > the
> > > > > > > netwrok interfaces.
> > > > > > >
> > > > > > > the port binding is updated after the migration is complete in
> > > > > > > post_livemigration
> > > > > > > in rocky+ neutron optionally uses the multiple port bindings
> flow to
> > > > > > > prebind the port to the destiatnion
> > > > > > > so it can update the xml if needed and if post copy live
> migration is
> > > > > > > enable it will asyconsly activate teh dest port
> > > > > > > binding before post_livemigration shortenting the downtime.
> > > > > > >
> > > > > > > if you are using the iptables firewall os-vif will have
> precreated
> > > >
> > > > the
> > > > > > > ovs port and intermediate linux bridge before the
> > > > > > > migration started which will allow neutron to wire it up (put
> it on
> > > >
> > > > the
> > > > > > > correct vlan and install security groups) before
> > > > > > > the vm completes the migraton.
> > > > > > >
> > > > > > > if you are using the ovs firewall os-vif still precreates teh
> ovs
> > > >
> > > > port
> > > > > > > but libvirt deletes it and recreats it too.
> > > > > > > as a result there is a race when using openvswitch firewall
> that can
> > > > > > > result in the RARP packets being lost.
> > > > > > >
> > > > > > > >
> > > > > > > > Best Regards
> > > > > > > > Ignazio Cassano
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Il giorno lun 27 apr 2020 alle ore 19:50 Sean Mooney <
> > > > > > >
> > > > > > > smooney at redhat.com<mailto:smooney at redhat.com>>
> > > > > > > > ha scritto:
> > > > > > > >
> > > > > > > > > On Mon, 2020-04-27 at 18:19 +0200, Ignazio Cassano wrote:
> > > > > > > > > > Hello, I have this problem with rocky or newer with
> > > >
> > > > iptables_hybrid
> > > > > > > > > > firewall.
> > > > > > > > > > So, can I solve using post copy live migration ???
> > > > > > > > >
> > > > > > > > > so this behavior has always been how nova worked but rocky
> the
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > >
> > > >
> > > >
> https://specs.openstack.org/openstack/nova-specs/specs/rocky/implemented/neutron-new-port-binding-api.html
> > > > > > > > > spec intoduced teh ablity to shorten the outage by pre
> biding the
> > > > > > >
> > > > > > > port and
> > > > > > > > > activating it when
> > > > > > > > > the vm is resumed on the destiation host before we get to
> pos
> > > >
> > > > live
> > > > > > >
> > > > > > > migrate.
> > > > > > > > >
> > > > > > > > > this reduces the outage time although i cant be fully
> elimiated
> > > >
> > > > as
> > > > > > >
> > > > > > > some
> > > > > > > > > level of packet loss is
> > > > > > > > > always expected when you live migrate.
> > > > > > > > >
> > > > > > > > > so yes enabliy post copy live migration should help but be
> aware
> > > >
> > > > that
> > > > > > >
> > > > > > > if a
> > > > > > > > > network partion happens
> > > > > > > > > during a post copy live migration the vm will crash and
> need to
> > > >
> > > > be
> > > > > > > > > restarted.
> > > > > > > > > it is generally safe to use and will imporve the migration
> > > >
> > > > performace
> > > > > > >
> > > > > > > but
> > > > > > > > > unlike pre copy migration if
> > > > > > > > > the guess resumes on the dest and the mempry page has not
> been
> > > >
> > > > copied
> > > > > > >
> > > > > > > yet
> > > > > > > > > then it must wait for it to be copied
> > > > > > > > > and retrive it form the souce host. if the connection too
> the
> > > >
> > > > souce
> > > > > > >
> > > > > > > host
> > > > > > > > > is intrupted then the vm cant
> > > > > > > > > do that and the migration will fail and the instance will
> crash.
> > > >
> > > > if
> > > > > > >
> > > > > > > you
> > > > > > > > > are using precopy migration
> > > > > > > > > if there is a network partaion during the migration the
> > > >
> > > > migration will
> > > > > > > > > fail but the instance will continue
> > > > > > > > > to run on the source host.
> > > > > > > > >
> > > > > > > > > so while i would still recommend using it, i it just good
> to be
> > > >
> > > > aware
> > > > > > >
> > > > > > > of
> > > > > > > > > that behavior change.
> > > > > > > > >
> > > > > > > > > > Thanks
> > > > > > > > > > Ignazio
> > > > > > > > > >
> > > > > > > > > > Il Lun 27 Apr 2020, 17:57 Sean Mooney <
> smooney at redhat.com<mailto:smooney at redhat.com>> ha
> > > > > > >
> > > > > > > scritto:
> > > > > > > > > >
> > > > > > > > > > > On Mon, 2020-04-27 at 17:06 +0200, Ignazio Cassano
> wrote:
> > > > > > > > > > > > Hello, I have a problem on stein neutron. When a vm
> migrate
> > > > > > >
> > > > > > > from one
> > > > > > > > >
> > > > > > > > > node
> > > > > > > > > > > > to another I cannot ping it for several minutes. If
> in the
> > > >
> > > > vm I
> > > > > > >
> > > > > > > put a
> > > > > > > > > > > > script that ping the gateway continously, the live
> > > >
> > > > migration
> > > > > > >
> > > > > > > works
> > > > > > > > >
> > > > > > > > > fine
> > > > > > > > > > >
> > > > > > > > > > > and
> > > > > > > > > > > > I can ping it. Why this happens ? I read something
> about
> > > > > > >
> > > > > > > gratuitous
> > > > > > > > >
> > > > > > > > > arp.
> > > > > > > > > > >
> > > > > > > > > > > qemu does not use gratuitous arp but instead uses an
> older
> > > > > > >
> > > > > > > protocal
> > > > > > > > >
> > > > > > > > > called
> > > > > > > > > > > RARP
> > > > > > > > > > > to do mac address learning.
> > > > > > > > > > >
> > > > > > > > > > > what release of openstack are you using. and are you
> using
> > > > > > >
> > > > > > > iptables
> > > > > > > > > > > firewall of openvswitch firewall.
> > > > > > > > > > >
> > > > > > > > > > > if you are using openvswtich there is is nothing we
> can do
> > > >
> > > > until
> > > > > > >
> > > > > > > we
> > > > > > > > > > > finally delegate vif pluging to os-vif.
> > > > > > > > > > > currently libvirt handels interface plugging for
> kernel ovs
> > > >
> > > > when
> > > > > > >
> > > > > > > using
> > > > > > > > >
> > > > > > > > > the
> > > > > > > > > > > openvswitch firewall driver
> > > > > > > > > > > https://review.opendev.org/#/c/602432/ would adress
> that
> > > >
> > > > but it
> > > > > > >
> > > > > > > and
> > > > > > > > >
> > > > > > > > > the
> > > > > > > > > > > neutron patch are
> > > > > > > > > > > https://review.opendev.org/#/c/640258 rather out
> dated.
> > > >
> > > > while
> > > > > > >
> > > > > > > libvirt
> > > > > > > > >
> > > > > > > > > is
> > > > > > > > > > > pluging the vif there will always be
> > > > > > > > > > > a race condition where the RARP packets sent by qemu
> and
> > > >
> > > > then mac
> > > > > > > > >
> > > > > > > > > learning
> > > > > > > > > > > packets will be lost.
> > > > > > > > > > >
> > > > > > > > > > > if you are using the iptables firewall and you have
> opnestack
> > > > > > >
> > > > > > > rock or
> > > > > > > > > > > later then if you enable post copy live migration
> > > > > > > > > > > it should reduce the downtime. in this conficution we
> do not
> > > >
> > > > have
> > > > > > >
> > > > > > > the
> > > > > > > > >
> > > > > > > > > race
> > > > > > > > > > > betwen neutron and libvirt so the rarp
> > > > > > > > > > > packets should not be lost.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > > Please, help me ?
> > > > > > > > > > > > Any workaround , please ?
> > > > > > > > > > > >
> > > > > > > > > > > > Best Regards
> > > > > > > > > > > > Ignazio
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > > >
> > > >
> > > >
> >
>
>
>
>
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