Neutron + OVN raft cluster

Tiago Pires tiagohp at gmail.com
Mon May 9 19:39:55 UTC 2022


Hi all,

Thanks Terry.
As I'm using an old OVS (2.13)/OVN(20.3) version due openstack release
(Ussuri), would it be possible to upgrade only the OVN/OVS without
upgrading the whole openstack?
I'm only checking options in this case, how are you guys dealing with this
in production?

Regards,

Tiago Pires

Em seg., 9 de mai. de 2022 às 10:45, Terry Wilson <twilson at redhat.com>
escreveu:

> Sorry, I was on PTO. Jakub is right, w/o using python-ovs 2.17, when
> ovs breaks the connection for the leadership clients will re-download
> the entire content of their registered tables. With 2.17,
> monitor-cond-since/update3 support is added to python-ovs and it
> should just download the changes since they reconnected. As long as
> the client code handles reconnections, this reconnecting should not be
> an issue. It is still possible that there is code that doesn't
> properly handle reconnections in general, but I'd start with trying
> ovs 2.17. The disonnections will always happen, but they shouldn't
> break things.
>
> On Fri, May 6, 2022 at 5:13 PM Tiago Pires <tiagohp at gmail.com> wrote:
> >
> > Hi Mohammed,
> >
> > It seems a little bit like our issue.
> >
> > Thank you.
> >
> > Tiago Pires
> >
> > Em sex., 6 de mai. de 2022 às 18:21, Mohammed Naser <mnaser at vexxhost.com>
> escreveu:
> >>
> >> Hi Tiago,
> >>
> >> Have you seen this?
> >>
> >> https://bugs.launchpad.net/nova/+bug/1969592
> >>
> >> Mohammed
> >>
> >> On Fri, May 6, 2022 at 3:56 PM Tiago Pires <tiagohp at gmail.com> wrote:
> >> >
> >> > Hi all,
> >> >
> >> > I was checking the mail list history and this thread
> https://mail.openvswitch.org/pipermail/ovs-discuss/2018-March/046438.html
> caught my attention about raft ovsdb clustering.
> >> > In my setup (OVN 20.03 and Openstack Ussuri) on the ovn-controller we
> have configured the
> ovn-remote="tcp:10.2X.4X.4:6642,tcp:10.2X.4X.68:6642,tcp:10.2X.4X.132:6642"
> with the 3 OVN central member that they are in cluster mode.
> >> > Also on the neutron ML2 side:
> >> > [ovn]
> >> > ovn_native_dhcp = True
> >> > ovn_nb_connection =
> tcp:10.2X.4X.4:6641,tcp:10.2X.4X.68:6641,tcp:10.2X.4X.132:6641
> >> > ovn_sb_connection =
> tcp:10.2X.4X.4:6642,tcp:10.2X.4X.68:6642,tcp:10.2X.4X.132:6642
> >> >
> >> > We are experiencing an issue with Neutron when the OVN leader decide
> to take a snapshot and by design another member became leader(more less
> every 8 minutes):
> >> > 2022-05-05T16:57:42.135Z|17401|raft|INFO|Transferring leadership to
> write a snapshot.
> >> >
> >> > ovs-appctl -t /var/run/ovn/ovnsb_db.ctl cluster/status OVN_Southbound
> >> > 4a03
> >> > Name: OVN_Southbound
> >> > Cluster ID: ca74 (ca744caf-40cd-4751-a2f2-86e35ad6541c)
> >> > Server ID: 4a03 (4a0328dc-e9a4-495e-a4f1-0a0340fc6d19)
> >> > Address: tcp:10.2X.4X.132:6644
> >> > Status: cluster member
> >> > Role: leader
> >> > Term: 1912
> >> > Leader: self
> >> > Vote: self
> >> >
> >> > Election timer: 10000
> >> > Log: [497643, 498261]
> >> > Entries not yet committed: 0
> >> > Entries not yet applied: 0
> >> > Connections: ->3d6c ->4ef0 <-3d6c <-4ef0
> >> > Servers:
> >> >     4a03 (4a03 at tcp:10.2X.4X.132:6644) (self) next_index=497874
> match_index=498260
> >> >     3d6c (3d6c at tcp:10.2X.4X.68:6644) next_index=498261
> match_index=498260
> >> >     4ef0 (4ef0 at tcp:10.2X.4X.4:6644) next_index=498261
> match_index=498260
> >> >
> >> > As I understood the tcp connections from the Neutron (NB) and
> ovn-controllers (SB) to OVN Central are established only with the leader:
> >> >
> >> > #OVN central leader
> >> > $ netstat -nap | grep 6642| more
> >> >
> >> > tcp        0      0 0.0.0.0:6642            0.0.0.0:*
>  LISTEN      -
> >> > tcp        0      0 10.2X.4X.132:6642       10.24.40.17:47278
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.24.40.76:36240
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.17:47280
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.6:43102
> ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.75:58890
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.6:43108
> ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.17:47142
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.71:48808
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.132:6642       10.2X.4X.17:47096
>  ESTABLISHED -
> >> > #OVN follower 2
> >> >
> >> > $ netstat -nap | grep 6642
> >> >
> >> > tcp        0      0 0.0.0.0:6642            0.0.0.0:*
>  LISTEN      -
> >> > tcp        0      0 10.2X.4X.4:6642         10.2X.4X.76:57256
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.4:6642         10.2X.4X.134:54026
> ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.4:6642         10.2X.4X.10:34962
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.4:6642         10.2X.4X.6:49238
> ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.4:6642         10.2X.4X.135:59972
> ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.4:6642         10.2X.4X.75:40162
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.4:39566        10.2X.4X.132:6642
>  ESTABLISHED -
> >> > #OVN follower 3
> >> >
> >> > netstat -nap | grep 6642
> >> >
> >> > tcp        0      0 0.0.0.0:6642            0.0.0.0:*
>  LISTEN      -
> >> > tcp        0      0 10.2X.4X.68:6642        10.2X.4X.70:40750
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.68:6642        10.2X.4X.11:49718
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.68:45632       10.2X.4X.132:6642
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.68:6642        10.2X.4X.16:44816
>  ESTABLISHED -
> >> > tcp        0      0 10.2X.4X.68:6642        10.2X.4X.7:45216
> ESTABLISHED
> >> >
> >> > The issue that we are experiencing is on the neutron-server that
> disconnects when there is the ovn leader change (due snapshot like each 8
> minutes) and reconnects to the next leader. It breaks the Openstack API
> when someone is trying to create a VM at the same time.
> >> > First, is my current configuration correct? Should the leader change
> and break the neutron side? Or is there some missing configuration?
> >> > I was wondering if it is possible to use a LB with VIP and this VIP
> balance the connections to the ovn central members and I would reconfigure
> on the neutron side only with the VIP and also on the ovs-controllers. Does
> that make sense?
> >> >
> >> > Thank you.
> >> >
> >> > Regards,
> >> >
> >> > Tiago Pires
> >>
> >>
> >>
> >> --
> >> Mohammed Naser
> >> VEXXHOST, Inc.
>
>
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