[mos] openvswitch agent fails with bridges longer than 11 chars

[Kevin Benton]

The openvswitch agent will try to construct veth pairs with names longer than the maximum allowed (15) and fail. VMs will then have no external connectivity.

This happens in cases where the bridge name is very long (e.g. int-br-bonded).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/98911

[Kevin Benton (kevinbenton)]

Here is an example:

$ ip link add int-int-br-bonded type veth peer name phy-int-br-bonded
Error: argument "peer" is wrong: "name" too long

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/98911
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=1222366f6dadf7ce2a810c919344054196134db8
Submitter: Jenkins
Branch: master

commit 1222366f6dadf7ce2a810c919344054196134db8
Author: Kevin Benton <email address hidden>
Date: Fri Jun 6 08:15:38 2014 -0700

    OVS Agent: limit veth names to 15 chars

    The maximum length of a veth interface name is 15 characters.
    This patch limits the length of the veth names created for
    integration bridges by switching to a fixed-length hashing
    mechanism if the normal name would exceed the allowed length.

    Closes-Bug: #1328288
    Change-Id: I432cee62a6dc91f268becbc91f8024c23dd0bfac

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/99273

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/99273
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=ca7ed8f84da6962a9c2b8ad21d484931d297f31b
Submitter: Jenkins
Branch: stable/icehouse

commit ca7ed8f84da6962a9c2b8ad21d484931d297f31b
Author: Kevin Benton <email address hidden>
Date: Fri Jun 6 08:15:38 2014 -0700

    OVS Agent: limit veth names to 15 chars

    The maximum length of a veth interface name is 15 characters.
    This patch limits the length of the veth names created for
    integration bridges by switching to a fixed-length hashing
    mechanism if the normal name would exceed the allowed length.

    Closes-Bug: #1328288
    Change-Id: I432cee62a6dc91f268becbc91f8024c23dd0bfac
    (cherry-picked from 1222366f6dadf7ce2a810c919344054196134db8)

[Vladimir Kuklin (vkuklin)]

I am not sure that this bug affects Mirantis OpenStack distribution as we are using OVS 1.10 which creates patch interfaces in userspace, thus avoiding intereference with kernel limits. We need to recheck if it reproduces on MOS environments.

[Kevin Benton (kevinbenton)]

The openvswitch agent for Neutron Icehouse doesn't leverage patch interfaces.

I have already fixed this on the Neutron side and back-ported to Icehouse[1] so I'm not sure it needs to be high-priority (assuming Fuel grabs the Icehouse updates). This is especially true because we were doing a non-standard deployment by skipping the br-priv bridge that is normally used between the physical interface bridge and br-int. i.e. it was only a problem when the ovs agent was configured to patch directly to the br0--ovs-bond0 bridge for one of the physnets.

1. https://github.com/openstack/neutron/commit/ca7ed8f84da6962a9c2b8ad21d484931d297f31b

[Andrey Epifanov (aepifanov)]

Fix committed as a part of merge with stable/icehouse branch:
https://bugs.launchpad.net/mos/+bug/1344037