yahoo-eng-team team mailing list archive

[Ian Wells <iawells@xxxxxxxxx>]

Public bug reported:

(This is using the ML2 driver with the Linuxbridge agent, along with
libvirt and KVM.  This is likely to be agent-specific, but I think at
least some other agents will have the problem.)

1. set Neutron's network_device_mtu to (say) 9000, assuming you've set up an infrastructure that will pass large MTU packets
2. create a network
3. create two VMs on the network
4. attempt to pass large packets

This won't work.  The reason it won't work is because, although the
Linuxbridge agent does attempt to apply network_device_mtu to the tap
interfaces, it's not registered the relevant config item definitions
from neutron.agent.linux.interfaces, so the value is silently ignored
when the config files are read.


Registering the OPTS block from the interfaces.py file certainly fixes the issue, but is likely to have other effects, since there are several other config files in there that are at present ignored by the agent.

** Affects: neutron
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1348788

Title:
  network_device_mtu is not applied to VMs, only to agents

Status in OpenStack Neutron (virtual network service):
  New

Bug description:
  (This is using the ML2 driver with the Linuxbridge agent, along with
  libvirt and KVM.  This is likely to be agent-specific, but I think at
  least some other agents will have the problem.)

  1. set Neutron's network_device_mtu to (say) 9000, assuming you've set up an infrastructure that will pass large MTU packets
  2. create a network
  3. create two VMs on the network
  4. attempt to pass large packets

  This won't work.  The reason it won't work is because, although the
  Linuxbridge agent does attempt to apply network_device_mtu to the tap
  interfaces, it's not registered the relevant config item definitions
  from neutron.agent.linux.interfaces, so the value is silently ignored
  when the config files are read.

  
  Registering the OPTS block from the interfaces.py file certainly fixes the issue, but is likely to have other effects, since there are several other config files in there that are at present ignored by the agent.

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