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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> 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> 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>
>> > 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> 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>
>> > > > > 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>
>> > > > > > > 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>
>> 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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