yahoo-eng-team team mailing list archive

[Rodolfo Alonso <ralonsoh@xxxxxxxxxx>]

Public bug reported:

This bug is related to:
- https://bugs.launchpad.net/neutron/+bug/1828755
- https://bugs.launchpad.net/neutron/+bug/1627480

BUG DESCRIPTION.
We have a deployment where, during the DHCP agent restart, some DHCP namespace ports are synchronized without any reason. This bug is reported in [1].

When the DHCP agent is restarted, the port information passed to the agent does not contain the correct "fixed_ips" parameter:
Requested DHCP port with IPs on subnets set([u'xxxxxxxxxx']) but only got IPs on subnets set([])

However, this port, used before the restart as the DHCP namespace port,
is never modified and the "fixed_ips" should be the same. When this
happens, the whole namespace is resync; this takes around 30 seconds
just to retrieve the server information and setup the DHCP port again.


MITIGATION.
In order to mitigate (not to solve) this issue, I'll propose a patch to, when [2] happens, make a RPC call to retrieve only the DHCP port from the server DB. If the port information is correct (an updated), the method should continue avoiding the exception SubnetMismatchForPort.


[1] https://bugzilla.redhat.com/show_bug.cgi?id=1741373
[2] https://github.com/openstack/neutron/blob/4f6b8bb3e55dfa564e87d90e4c1257d0153ef141/neutron/agent/linux/dhcp.py#L1426

** Affects: neutron
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/1841636

Title:
  DHCP port information incomplete during the DHCP port setup

Status in neutron:
  New

Bug description:
  This bug is related to:
  - https://bugs.launchpad.net/neutron/+bug/1828755
  - https://bugs.launchpad.net/neutron/+bug/1627480

  BUG DESCRIPTION.
  We have a deployment where, during the DHCP agent restart, some DHCP namespace ports are synchronized without any reason. This bug is reported in [1].

  When the DHCP agent is restarted, the port information passed to the agent does not contain the correct "fixed_ips" parameter:
  Requested DHCP port with IPs on subnets set([u'xxxxxxxxxx']) but only got IPs on subnets set([])

  However, this port, used before the restart as the DHCP namespace
  port, is never modified and the "fixed_ips" should be the same. When
  this happens, the whole namespace is resync; this takes around 30
  seconds just to retrieve the server information and setup the DHCP
  port again.

  
  MITIGATION.
  In order to mitigate (not to solve) this issue, I'll propose a patch to, when [2] happens, make a RPC call to retrieve only the DHCP port from the server DB. If the port information is correct (an updated), the method should continue avoiding the exception SubnetMismatchForPort.


  [1] https://bugzilla.redhat.com/show_bug.cgi?id=1741373
  [2] https://github.com/openstack/neutron/blob/4f6b8bb3e55dfa564e87d90e4c1257d0153ef141/neutron/agent/linux/dhcp.py#L1426

To manage notifications about this bug go to:
https://bugs.launchpad.net/neutron/+bug/1841636/+subscriptions