[Bug 1993480] Re: Multiple ct_clear datapath actions (openvswitch: ovs-system: deferred action limit reached, drop recirc action)

[Trent Lloyd]

** Also affects: cloud-archive
   Importance: Undecided
       Status: New

** Also affects: cloud-archive/victoria
   Importance: Undecided
       Status: New

** Also affects: cloud-archive/ussuri
   Importance: Undecided
       Status: New

** Also affects: cloud-archive/wallaby
   Importance: Undecided
       Status: New

** Changed in: cloud-archive/ussuri
       Status: New => Confirmed

** Changed in: cloud-archive/victoria
       Status: New => Confirmed

** Changed in: cloud-archive/wallaby
       Status: New => Confirmed

** Changed in: openvswitch (Ubuntu)
       Status: New => Confirmed

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https://bugs.launchpad.net/bugs/1993480

Title:
  Multiple ct_clear datapath actions (openvswitch: ovs-system: deferred
  action limit reached, drop recirc action)

Status in Ubuntu Cloud Archive:
  New
Status in Ubuntu Cloud Archive ussuri series:
  Confirmed
Status in Ubuntu Cloud Archive victoria series:
  Confirmed
Status in Ubuntu Cloud Archive wallaby series:
  Confirmed
Status in openvswitch package in Ubuntu:
  Confirmed

Bug description:
  The following log message is commonly encountered 100s of times per day on OVN/OpenStack deployments:
  openvswitch: ovs-system: deferred action limit reached, drop recirc action

  This message may appear despite seeming to have no impact VM traffic.
  One known cause of this message is that generated dataplane flow
  contains many (4-17+) repeated ct_clear actions.

  You can verify you have such flows as follows:
  ovs-appctl dpctl/dump-flows -m |grep -E "(ct_clear[,]){2,}"

  This was fixed upstream in the following commit:
  https://github.com/openvswitch/ovs/commit/355fef6f2ccbcf78797b938421cb4cef9b59af13
  355fef6f2 ofproto-dpif-xlate: Avoid successive ct_clear datapath actions.

  There is an additional Fixes commit:
  https://github.com/openvswitch/ovs/commit/88e3ae5d6f7370acbf1d9d60c1a06e4132e4e532
  88e3ae5d6 ofproto-dpif-xlate: Fix internal CT state for non-recirc traffic.

  
  While traffic seems unaffected, it's unclear how much a performance loss there is in these cases.

  This occurs at least as far back as Focal/Usurri, upstream has
  backports to many releases. We should look to backport it to at least
  Focal/Ussuri (openvswitch v2.13)

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