GRE tunneling is broken if hosts are on multiple subnets (multi-homed)
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
neutron |
Fix Released
|
Medium
|
Adin Scannell |
Bug Description
Basic setup:
* Bunch of hosts on subnet X
* Host on subnet X and subnet Y (controller)
* Bunch of hosts on subnet Y
If local_ip for controller is from subnet X, then GRE tunnels are broken from controller to subnet Y.
-- more detail --
Because you can only specify a single local_ip when using GRE tunneling in openvswitch and this information is propagated to all hosts regardless of their subnet -- allowing GRE to choose the local_ip for tunnels results in one-directional flows because the IP won't be recognized (as one or more hosts may be sending traffic on an IP that is not their recognized local_ip).
There is a pretty straight-forward fix -- the local_ip should be specified for all GRE tunnels, that way all traffic will originate from the IP that the hosts in the cluster are aware of. The local_ip needs to be routable from all hosts, but this is no different than before. There are more complex ways of dealing with this problem, but I think that this is the right fix and keeps it simple.
I will be submitting a fix shortly via Gerrit.
description: | updated |
tags: | added: ovs |
Changed in neutron: | |
importance: | Undecided → Medium |
status: | New → Triaged |
Changed in neutron: | |
milestone: | none → icehouse-1 |
milestone: | icehouse-1 → 2013.2.1 |
Changed in neutron: | |
status: | Fix Committed → Fix Released |
assignee: | nobody → Adin Scannell (amscanne) |
Changed in neutron: | |
milestone: | 2013.2.1 → 2013.2 |
Patch submitted: /review. openstack. org/#/c/ 30637/
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