On Mon, Jun 5, 2023 at 8:58 AM Vladislav Odintsov <[email protected]> wrote:
>
> Hi Dumitru, Ilya, Han,
>
> do you guys have any comments here?
> I’m gonna start working on this change in near future...
>
> Thank you.
>
> On 17 May 2023, at 18:34, Numan Siddique <[email protected]> wrote:
>
> On Wed, May 17, 2023 at 4:44 AM Vladislav Odintsov <[email protected]>
wrote:
>
>
>
>
> On 16 May 2023, at 23:54, Numan Siddique <[email protected]> wrote:
>
> Hi Vladislav,
>
> Sorry for the late reply.
>
> PSB for few comments.
>
>
>
> Thanks for your reply!
> My answers are inline.
>
>
>
>
> On Tue, May 16, 2023 at 3:42 PM Vladislav Odintsov <[email protected]
<mailto:[email protected]>> wrote:
>
>
> Hi Numan, Dumitru, Ilya,
>
> I guess I’ve managed to deal with some of these problems and have some
conclusions.
> Please see inline.
>
> On 14 Apr 2023, at 16:26, Vladislav Odintsov <[email protected]> wrote:
>
> And as a follow-up, I see sometimes next error message in ovn-controller
log, though there is a configured much higher limit in seconds for
inactivity probe value for the chassis:
>
>
> ovn-controller establishes 3 openflow connections to local ovs-vswitchd
for next purposes:
> 1. openflow rules management (openflow probe interval is configured
through ovn-openflow-probe-interval external_ids setting [1]; default —
disabled [2]);
> 2. openflow features collection (hardcoded probe interval 5s [3]);
> 3. pinctrl thread (hardcoded probe interval 5s [4]).
>
> ovs|04426|rconn|ERR|unix:/run/openvswitch/br-int.mgmt: no response to
inactivity probe after 8 seconds, disconnecting
>
> ovs|26560|rconn|ERR|unix:/run/openvswitch/br-int.mgmt: no response to
inactivity probe after 10 seconds, disconnecting
>
>
> These messages most likely related to the connection for features
collection or pinctrl thread. So ovn-openflow-probe-interval has no matter
here.
>
>
> server with first log message:
> # ovs-vsctl get open . external_ids:ovn-openflow-probe-interval
> "30"
>
> server with second log message:
> # ovs-vsctl get open . external_ids:ovn-openflow-probe-interval
> "60"
>
>
>
> On 30 Mar 2023, at 23:19, Vladislav Odintsov <[email protected]> wrote:
>
> Hi all,
>
> I’m facing a false positive failover in the event of openflow connection
got dropped after inactivity probe timeout due to high load of
ovn-controller handling huge amount of ovsdb updates.
> I wonder wether its a bug or I have to tune any specifics. See
ovn-controller logs:
>
> 2023-03-30T07:57:24.469Z|58440|inc_proc_eng|INFO|node:
logical_flow_output, recompute (failed handler for input port_groups) took
35774ms
> 2023-03-30T07:57:28.521Z|58441|lflow_cache|INFO|Detected cache inactivity
(last active 40006 ms ago): trimming cache
> 2023-03-30T07:57:28.528Z|58442|timeval|WARN|Unreasonably long 40084ms
poll interval (32947ms user, 6968ms system)
> 2023-03-30T07:57:28.528Z|58443|timeval|WARN|faults: 43468 minor, 0 major
> …..
> 2023-03-30T07:57:48.784Z|58496|reconnect|ERR|ssl:xxxx:6642: no response
to inactivity probe after 60.2 seconds, disconnecting
> 2023-03-30T07:57:48.784Z|58497|reconnect|INFO|ssl:xxxx:6642: connection
dropped
> 2023-03-30T07:57:48.905Z|58498|main|INFO|OVNSB commit failed, force
recompute next time.
> 2023-03-30T07:57:49.786Z|58499|reconnect|INFO|ssl:yyyy:6642: connecting...
> 2023-03-30T07:57:49.924Z|58500|reconnect|INFO|ssl:yyyy:6642: connected
> 2023-03-30T07:57:29.781Z|58501|poll_loop|INFO|wakeup due to 0-ms timeout
at lib/stream-ssl.c:838 (74% CPU usage)
> 2023-03-30T07:57:29.836Z|58502|poll_loop|INFO|wakeup due to 0-ms timeout
at lib/stream-ssl.c:838 (74% CPU usage)
> ….
> 2023-03-30T07:57:05.976Z|58545|poll_loop|INFO|wakeup due to 0-ms timeout
at lib/stream-ssl.c:838 (101% CPU usage)
> 2023-03-30T07:57:07.002Z|58546|memory|INFO|peak resident set size grew
54% in last 682257.2 seconds, from 4435696 kB to 6824820 kB
>
2023-03-30T07:57:07.002Z|58547|memory|INFO|idl-cells-OVN_Southbound:11491359
idl-cells-Open_vSwitch:14416 lflow-cache-entries-cache-expr:530298
lflow-cache-entries-cache-matches:31770 lflow-cache-size-KB:769553
local_datapath_usage-KB:630
> ofctrl_desired_flow_usage-KB:577052 ofctrl_installed_flow_usage-KB:409538
ofctrl_sb_flow_ref_usage-KB:273707
> …
>
2023-03-30T07:57:31.667Z|58552|rconn|WARN|unix:/run/openvswitch/br-int.mgmt:
connection dropped (Broken pipe)
> 2023-03-30T07:57:31.739Z|58553|binding|INFO|Releasing lport cr-xxx from
this chassis (sb_readonly=0)
> 2023-03-30T07:57:31.739Z|58554|if_status|WARN|Dropped 1 log messages in
last 1254725 seconds (most recently, 1254725 seconds ago) due to excessive
rate
> 2023-03-30T07:57:31.739Z|58555|if_status|WARN|Trying to release unknown
interface cr-xxx
> 2023-03-30T07:57:31.743Z|58556|binding|INFO|Releasing lport cr-yyy from
this chassis (sb_readonly=0)
> 2023-03-30T07:57:31.743Z|58557|binding|INFO|Releasing lport cr-zzz from
this chassis (sb_readonly=0)
> …
>
> After some time these ports are claimed back:
>
>
2023-03-30T07:57:49.320Z|59137|rconn|INFO|unix:/run/openvswitch/br-int.mgmt:
connecting...
>
2023-03-30T07:57:49.320Z|59138|rconn|INFO|unix:/run/openvswitch/br-int.mgmt:
connected
> 2023-03-30T07:57:49.523Z|59139|poll_loop|INFO|wakeup due to 0-ms timeout
at controller/ovn-controller.c:4296 (99% CPU usage)
> 2023-03-30T07:57:49.574Z|59140|poll_loop|INFO|wakeup due to 0-ms timeout
at controller/ovn-controller.c:4286 (99% CPU usage)
> 2023-03-30T07:58:01.451Z|59141|poll_loop|INFO|wakeup due to [POLLIN] on
fd 22 (xxxx:34736<->yyyy:6642) at lib/stream-ssl.c:836 (99% CPU usage)
> 2023-03-30T07:58:02.449Z|59142|binding|INFO|Claiming lport cr-xxx for
this chassis.
> 2023-03-30T07:58:02.449Z|59143|binding|INFO|cr-xxx: Claiming
xx:xx:xx:xx:xx x.x.x.x/xx
> 2023-03-30T07:58:02.453Z|59144|binding|INFO|Claiming lport cr-yyy for
this chassis.
> 2023-03-30T07:58:02.453Z|59145|binding|INFO|cr-yyy: Claiming
yy:yy:yy:yy:yy:yy y.y.y.y/yy
> …
>
> Previously I’ve met with similar problem but the openflow probe interval
was 30 seconds and I set it to 60 and then to 120 seconds.
> But it seems that OVS was configured on default inactivity probe timeout
for openflow - 60 seconds. So, the error above occured. In OVS logs it
looks like next:
>
> 2023-03-30T07:57:28.632Z|61003|rconn|ERR|br-int<->unix#8: no response to
inactivity probe after 60 seconds, disconnecting
>
>
> When ovn-controller looses openflow connection for flows management it
considers OVS is dead and releases its ha-chassis-group bindings. This
logic was introduced with the patch [5].
>
> ovn-controller uses unix socket to connect to ovs-vswitchd OF socket, it
seems useless to configure inactivity probing, right?
> In this commit message [6] Han also disables OF inactivity probing by
default.
>
> Moreover, it seems harmful to configure inactivity probing from OVS to
ovn-controller and vise versa.
> In case ovn-controller for some reason is busy with some work and can’t
answer to OVS in two minutes (its default probe interval is 60s [7]), so
OVS destroys OF connection with the ERR log:
> ovs|18206|rconn|ERR|br-int<->unix#17574: no response to inactivity probe
after 60 seconds, disconnecting
>
> So, when ovn-controller resumes after a big work it sees that OF
connection is closed and triggers chassisredirect portbindings release.
> This leads to datapath downtime and unnesessary load on OVN_Southbound,
ovn-controllers, etc.
>
> To avoid such behaviour user may consider not to configure
ovn-openflow-probe-interval AND disable probing from OVS side with the next
command:
> ovs-vsctl --inactivity-probe=0 set-controller br-int
punix://var/run/openvswitch/br-int.mgmt

Did you test this? It seems for the management controller it is hardcoded
to 60s:
https://github.com/openvswitch/ovs/blob/master/vswitchd/bridge.c#L3882

>
> To make this setting applied, it’s needed to reestablish OF connection.
(for instance, restart ovn-controller)
>
> My proposal:
>
> If ovn-controller uses only unix socket for OF connection, it should be
safe to disable OF probing from its code:
> 1. configure controller for br-int to disable probing (ensure br-int or
other configured bridge controller created with inactivity probe = 0);

Do you mean the OVS side config (using ovs-vsctl)? But there is no code
change from OVN side, right?

> 2. delete ovn-openflow-probe-interval setting and mark in documentation
that for OVN versions >= 20.09 it’s recommended not to configure
ovn-openflow-inactivity-probe. For versions < 20.09 default interval is 5
seconds, so it’s reasonable to set it to higher value in the config for
loaded hypervisors;
>
I am ok with this. For the documentation, it should be ok to remove the
related description and update the NEWS. I think there is no need to
mention 20.09 or any specific version, because documentation always belongs
to the version where it is updated.

>
> You mean 23.09 right ?
>
>
> No.
> IIUC, the 20.03.0-2 and 20.06.0-2 versions have default interval of 5
seconds.
> All other versions have disabled OF probing by default.
> So my idea was to mention it in docs and recommend users of those
versions (with 5 seconds default) to disable OF manually by setting
ovs-vsctl set open . external_ids:ovn-openflow-probe-interval=0.
>
>
>
> 3. set openflow probe interval for ovs features and pinctrl OF connection
to 0 (disable probing);
>
I am ok with this, too.

> What do you guys think about this?
> Please, correct me if I understand something wrong and described changes
can’t be accepted.
>
>
> The proposal looks reasonable to me.
>
> There may be once concern.  Let's say the physical link is fine (where
> vswitchd runs bfd) but vswitchd is down on chassis 'A' for some
> reason.  With probing disabled, ovn-controller will never
> come to know if vswitchd is down until it tries to communicate with
> it.  If this chassis 'A' is acting as a gateway,  external traffic
> from other chassis VMs will be tunnelled to this and since vswitchd is
> down the traffic may not go out if no datapath flows exist to output
> the traffic to the physical interface of the provider bridge.  Is this
> acceptable ?
> At least with the probing enabled, ovn-controller will release the
> chassis resident port and the next in the priority will claim it.
>
> IMO,  this limitation is more acceptable than the issue you reported.
> Let's see what others have to say about this.
>
>
>
> I’m not sure I fully understand your idea about vswitchd down.
> I tried to send sigkill to ovs-vswitchd with probing disabled and
ovn-controller recognized the failure (connection closed by peer) and
released its chassisredirect port_binding (assuming another chassis by
priority claims it):
>
>
2023-05-17T08:37:10.134Z|00004|rconn(ovn_pinctrl0)|INFO|unix:/run/openvswitch/br-int.mgmt:
connection closed by peer
>
2023-05-17T08:37:10.134Z|00061|rconn|INFO|unix:/run/openvswitch/br-int.mgmt:
connection closed by peer
>
2023-05-17T08:37:10.134Z|00062|rconn|INFO|unix:/run/openvswitch/br-int.mgmt:
connection closed by peer
> 2023-05-17T08:37:10.135Z|00063|binding|INFO|Releasing lport cr-xxx from
this chassis (sb_readonly=0)
> 2023-05-17T08:37:10.135Z|00064|if_status|WARN|Trying to release unknown
interface cr-xxx
> 2023-05-17T08:37:10.135Z|00065|binding|INFO|Releasing lport cr-xxx from
this chassis (sb_readonly=0)
>
> Does such test look reasonable and covers your concern? If not, could you
describe it in more details, please?
>
>
> I think I misunderstood earlier.  Please ignore my comment.  So when
> ovs-vswitchd is killed, ovn-controller will detect it.
>
>
> Thanks
> Numan
>
>
>
>
>
>
>
>
>
> This node is a dedicated l3gateway which has is-interconn=true setting
(interconnection case) and has quite big openflow table around 2.7M flows.
>
> So, I’ve got some questions for OVN and OVS:
> 1. I couldn’t find in ovn-controller code where the logic of handling
openflow connection drop. It is a bug when after openflow connection drop
the claimed cr-ports are being released? I guess, yes. Can you please point
me to the corrent place of code to start investigating?

When openflow connection drops, ovn-controller would wait for it to
reconnect and then trigger a recompute. It seems expected behavior that the
cr-ports are released during this time.

> 2. I see almost the same openflow amount on each l3gateway with
interconnection role. Even l3gateways which have no allocated
cr-port-bindings have 2M+ openflow flows. Is it normal operation or it’s a
place for possible optimisation? I mean it seems that excess flows are
installed.
>
>
> There are a lot of mac_binding records, but the question is why these
flows still persist even if no datapaths are allocated to the node.
>

Does the l3gateway chassis that has no cr-port-bindings have any other
port-bindings at all? Did you observe same amount of flows if there is no
port-bindings after you restart ovn-controller?
I think there shouldn't be any flows if there is no port-bindings, but the
flows are expected if this l3gateway had port-bindings earlier and then
released them, because the incremental-processing doesn't take care of
removing local-datapaths not in use anymore.

>
> Maybe the datapath to which the mac binding records belong is in the
> ovn-controllers' "local_datapath"  [1] -
> https://github.com/ovn-org/ovn/blob/main/controller/local_data.h#L35
>
>
> Thanks, I’ll check that.
>
>
> 3. How to handle long OVS OF updates, which block inactivity probe for OF
connection and then got dropped? From ovn-controller it’s possible to
configure inactivity probe, is it possible and should I configure from
ovs-vswitchd side?

The probe is always two-sides. As you mentioned you can disable the probe
from ovn-controller side. From OVS side, for my understanding it is
hardcoded to 60s. (Please confirm if your ovs-vsctl command override the
setting)

Thanks,
Han

> 4. There is a warning on try to release unknown interface, which was
relased right before. Is it normal situation or also should be investigated?
>
>
> I think it can be ignored.  Maybe @Dumitru Ceara can correct me or
comment here
>
> Thanks
> Numan
>
>
>
> For points 2-4 I still haven’t found the answer yet. If someone knows the
answer, please share it.
>
>
> Thanks.
>
> Regards,
> Vladislav Odintsov
>
>
>
> Regards,
> Vladislav Odintsov
>
>
>
> 1: https://github.com/ovn-org/ovn/blob/v23.03.0/controller/ofctrl.c#L421
> 2:
https://github.com/ovn-org/ovn/blob/v23.03.0/controller/ovn-controller.c#L108
> 3: https://github.com/ovn-org/ovn/blob/v23.03.0/lib/features.c#L85
> 4: https://github.com/ovn-org/ovn/blob/v23.03.0/controller/pinctrl.c#L3479
> 5:
https://patchwork.ozlabs.org/project/openvswitch/patch/[email protected]/
> 6:
https://github.com/ovn-org/ovn/commit/b8af8549396e62d6523be18e104352e334825783
> 7: https://github.com/openvswitch/ovs/blob/v3.1.0/vswitchd/bridge.c#L3860
>
> Regards,
> Vladislav Odintsov
>
>
>
>
>
>
> Regards,
> Vladislav Odintsov
>
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>
>
>
> Regards,
> Vladislav Odintsov
>
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>
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>
>
>
> Regards,
> Vladislav Odintsov
>
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