ovn-controller: Disable ofctrl probe by default

[Frode Nordahl]

[Impact]
Service/host restart or upgrade of the ovn-host package may render a host participating in a OVN network unusable as the ovn-controller process fails to complete programming of the local Open vSwitch switch flows.

[Test Case]
The issue was discovered when migrating a 3-node OpenStack cloud with 1000 instances deployed in our test lab. A test case could be to repeat that setup.

[Regression Potential]
None, the change of behavior was introduced upstream in [0] and later reversed in [1]. Keeping an idle probe for a unix socket type connection is clearly unnecessary.

[Original Bug Report]
A change [0] prior to the release of OVN v20.03.0 introduced a change of behavior where the inactivity probe for the ofctrl connection defaults to 5 seconds. Since this normally is a unix socket the default was not to have a inactivity probe at all.

On a busy system a inactivity probe of 5 seconds is not enough for the OVN Controller to complete programming of the switch.

The change of behavior was corrected in [1] and I think it would be beneficial if Ubuntu backported this fix to the OVN package rather than having charms and/or end users work around the issue by manually configuring the timeout through the `external-ids:ovn-openflow-probe-interval` key in the Open_vSwitch table.

Symptoms of this problem is that a OVN controller is either unable to do initial programming of a switch for a host with many ports and flows or that updates are lost on a functional system. The following will be printed in the log:

2020-10-11T18:56:09.355Z|30186|rconn|ERR|unix:/var/run/openvswitch/br-int.mgmt: no response to inactivity probe after 5 seconds, disconnecting

0: https://github.com/ovn-org/ovn/commit/c99069c8934c9ea55d310a8b6d48fb66aa477589
1: https://github.com/ovn-org/ovn/commit/b8af8549396e62d6523be18e104352e334825783

[Frode Nordahl (fnordahl)]

The fix is in 20.09 and has already been backported upstream to 20.06 and 20.03:

branch-20.03: https://github.com/ovn-org/ovn/commit/028d6db38ff56018ba40b3abb3da94ba7a724ffa
branch-20.06: https://github.com/ovn-org/ovn/commit/8cd56feadbc8644ece036784f78dd9be289c9fe9

[Brian Murray (brian-murray)]

Hello Frode, or anyone else affected,

Accepted ovn into groovy-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/ovn/20.06.2-0ubuntu1.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-groovy to verification-done-groovy. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-groovy. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Brian Murray (brian-murray)]

Hello Frode, or anyone else affected,

Accepted ovn into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/ovn/20.03.1-0ubuntu1.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Frode Nordahl (fnordahl)]

Verification done for Focal. Removed the workaround provided by the `external-ids:ovn-openflow-probe-interval` key in the Open_vSwitch table and installed the proposed package on a heavily loaded lab cluster and confirmed continued operation with the new package.

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for ovn has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ovn - 20.03.1-0ubuntu1.1

---------------
ovn (20.03.1-0ubuntu1.1) focal; urgency=medium

  * d/p/ovn-controller-ofctrl-probe-interval.patch: Cherry pick
    fix to disable ofctrl probe by default (LP: #1899369).

 -- Frode Nordahl <email address hidden> Fri, 06 Nov 2020 08:21:03 +0000

[Frode Nordahl (fnordahl)]

Have completed verification on Groovy too.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ovn - 20.06.2-0ubuntu1.1

---------------
ovn (20.06.2-0ubuntu1.1) groovy; urgency=medium

  * d/p/ovn-controller-ofctrl-probe-interval.patch: Cherry pick
    fix to disable ofctrl probe by default (LP: #1899369).

 -- Frode Nordahl <email address hidden> Fri, 06 Nov 2020 08:21:03 +0000

[Corey Bryant (corey.bryant)]

The verification of the Stable Release Update for ovn has completed successfully and the package has now been released to -updates. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Corey Bryant (corey.bryant)]

This bug was fixed in the package ovn - 20.03.1-0ubuntu1.1~cloud0
---------------

 ovn (20.03.1-0ubuntu1.1~cloud0) bionic-ussuri; urgency=medium
 .
   * New upstream release for the Ubuntu Cloud Archive.
 .
 ovn (20.03.1-0ubuntu1.1) focal; urgency=medium
 .
   * d/p/ovn-controller-ofctrl-probe-interval.patch: Cherry pick
     fix to disable ofctrl probe by default (LP: #1899369).
 .
 ovn (20.03.1-0ubuntu1) focal; urgency=medium
 .
   * New upstream point release (LP: #1897248).