yahoo-eng-team team mailing list archive

[Lucas Alvares Gomes <1892477@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

The nb_cfg as a mechanism to "ping" OVN control plane is very useful in
many ways. However, the current implementation will trigger update
notifications flooding in the whole control plane. Each HV updates to SB
the nb_cfg number and all these updates are notified to all the other
HVs, which is O(n^2). Although updates are batched in fewers
notifications than n^2, it still generates significant load on SB DB and
also on ovn-controllers.

In order to solve this problem the core OVN team created a new table
called Chassis_Private that holds the private information for the
chassis and is conditionally monitored by them. That way, updates to the
nb_cfg column will not affect all other hypervisors.

We need to make use of this new mechanism in the OVN driver.

** Affects: neutron
     Importance: High
     Assignee: Lucas Alvares Gomes (lucasagomes)
         Status: In Progress


** Tags: ovn

** Changed in: neutron
   Importance: Undecided => High

** Changed in: neutron
       Status: New => In Progress

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https://bugs.launchpad.net/bugs/1892477

Title:
  [OVN] Avoid nb_cfg update notification flooding during agents health
  check

Status in neutron:
  In Progress

Bug description:
  The nb_cfg as a mechanism to "ping" OVN control plane is very useful
  in many ways. However, the current implementation will trigger update
  notifications flooding in the whole control plane. Each HV updates to
  SB the nb_cfg number and all these updates are notified to all the
  other HVs, which is O(n^2). Although updates are batched in fewers
  notifications than n^2, it still generates significant load on SB DB
  and also on ovn-controllers.

  In order to solve this problem the core OVN team created a new table
  called Chassis_Private that holds the private information for the
  chassis and is conditionally monitored by them. That way, updates to
  the nb_cfg column will not affect all other hypervisors.

  We need to make use of this new mechanism in the OVN driver.

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