linuxbridge multinode depending on multicast support of provider

Bug #1683256 reported by Kevin Benton on 2017-04-17
18
This bug affects 3 people
Affects Status Importance Assigned to Milestone
neutron
High
omkar_telee

Bug Description

The way the Linux Bridge multinode job works right now, the VXLAN tenant networks are not using l2_population and subsequently rely on the multicast 'group' feature of kernel bridges for carrying broadcast traffic.

This would not normally be a problem, however, the local interface they are using to send this multicast traffic is the one attached directly to the provider cloud's network. So we are ultimately at the mercy of the provider's networks to carry multicast traffic between the multi-node instances, which is just asking for failures.

We need to adjust the job to setup a tunnel between the multinode instances to safely carry traffic between them like we do for DVR [1].

1. https://git.openstack.org/cgit/openstack-infra/devstack-gate/tree/devstack-vm-gate.sh#n149

This is likely leading to the instability of the LB multi-node job when the job is on certain cloud providers that might not have good multicast routing.

tags: added: gate-failure
Changed in neutron:
importance: Undecided → Critical
description: updated

It's not critical in that it doesn't affect a voting job. Lowering to High.

tags: added: linuxbridge
Changed in neutron:
importance: Critical → High
Changed in neutron:
status: New → Confirmed
Changed in neutron:
assignee: nobody → omkar_telee (omkar-telee)

We don't execute the job in gate, removing gate-failure tag.

tags: removed: gate-failure
Changed in neutron:
status: Confirmed → In Progress
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