[Bug 1965297] Re: l3ha don't set backup qg ports down

[Edward Hope-Morley]

** Description changed:

  The history to this request is as follows; bug 1916024 fixed an issue
  that subsequently had to be reverted due to a regression that it
  introduced (see bug 1927868) and the original issue can once again
  present itself in that keepalived is unable to send GARP on the qg port
  until the port is marked as UP by neutron which in loaded environments
  can sometimes take longer than keepalived will wait (e.g. when an
  l3-agent is restarted on a host that has hundreds of routers). The
  reason why qg- ports are marked as DOWN is because of the patch landed
  as part of bug 1859832 and as I understand it there is now consensus
  from upstream [1] to revert that patch as well and a better solution is
  needed to fix that particular issue. I have not found a bug open yet for
  the revert hence why I am opening this one.
  
  [1]
  https://meetings.opendev.org/meetings/neutron_drivers/2022/neutron_drivers.2022-03-04-14.03.log.txt
+ 
+ ------------
+ 
+ [Impact]
+ Please see LP bug description for full details but in short, this patch is a revert of a patch that has show instability in the field for users of Neutron L3HA.
+ 
+ [Test Plan]
+   * Deploy Openstack with Neutron L3 HA enabled
+   * Create a number of HA routers
+   * Check all qrouter namespaces and ensure that the qg- port is UP in all
+ 
+ [Regression Potential]
+ Since the original patch was intended to address issues with MLDv2 it is possible that reverting it will re-introduce those issues and a new patch will need to be proposed to address that.

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https://bugs.launchpad.net/bugs/1965297

Title:
  l3ha don't set backup qg ports down

Status in Ubuntu Cloud Archive:
  Triaged
Status in Ubuntu Cloud Archive xena series:
  In Progress
Status in Ubuntu Cloud Archive yoga series:
  Triaged
Status in Ubuntu Cloud Archive zed series:
  Triaged
Status in neutron:
  Fix Released
Status in neutron package in Ubuntu:
  Triaged
Status in neutron source package in Impish:
  Triaged
Status in neutron source package in Jammy:
  Triaged
Status in neutron source package in Kinetic:
  Triaged

Bug description:
  The history to this request is as follows; bug 1916024 fixed an issue
  that subsequently had to be reverted due to a regression that it
  introduced (see bug 1927868) and the original issue can once again
  present itself in that keepalived is unable to send GARP on the qg
  port until the port is marked as UP by neutron which in loaded
  environments can sometimes take longer than keepalived will wait (e.g.
  when an l3-agent is restarted on a host that has hundreds of routers).
  The reason why qg- ports are marked as DOWN is because of the patch
  landed as part of bug 1859832 and as I understand it there is now
  consensus from upstream [1] to revert that patch as well and a better
  solution is needed to fix that particular issue. I have not found a
  bug open yet for the revert hence why I am opening this one.

  [1]
  https://meetings.opendev.org/meetings/neutron_drivers/2022/neutron_drivers.2022-03-04-14.03.log.txt

  ------------

  [Impact]
  Please see LP bug description for full details but in short, this patch is a revert of a patch that has show instability in the field for users of Neutron L3HA.

  [Test Plan]
    * Deploy Openstack with Neutron L3 HA enabled
    * Create a number of HA routers
    * Check all qrouter namespaces and ensure that the qg- port is UP in all

  [Regression Potential]
  Since the original patch was intended to address issues with MLDv2 it is possible that reverting it will re-introduce those issues and a new patch will need to be proposed to address that.

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