Public bug reported: Setup:
We have 40+ compute nodes, all running neutron-l3-agent in DVR mode. We also have 1 node running neutron-l3-agent in DVR_SNAT mode. L2 population is happening with VXFLD (https://github.com/CumulusNetworks/vxfld). Steps to reproduce: After following the setup above, we noticed that traffic going to/from a floating IP was randomly going out the SNAT namespace (and thus getting connection resets). Further investigation showed this was related/correlated to traffic load, meaning, the more traffic, the more likely the return path would go out the SNAT namespace instead of back out the FIP namespace. After some searching, we found that conntrack was marking in-transit connections as "new" connections (losing their state, essentially) and thus the SNAT namespace would see this as new traffic and setup a new return path. ** Affects: neutron Importance: Undecided Assignee: David-wahlstrom (david-wahlstrom) Status: In Progress -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. https://bugs.launchpad.net/bugs/1620824 Title: Neutron DVR(SNAT) steals FIP traffic Status in neutron: In Progress Bug description: Setup: We have 40+ compute nodes, all running neutron-l3-agent in DVR mode. We also have 1 node running neutron-l3-agent in DVR_SNAT mode. L2 population is happening with VXFLD (https://github.com/CumulusNetworks/vxfld). Steps to reproduce: After following the setup above, we noticed that traffic going to/from a floating IP was randomly going out the SNAT namespace (and thus getting connection resets). Further investigation showed this was related/correlated to traffic load, meaning, the more traffic, the more likely the return path would go out the SNAT namespace instead of back out the FIP namespace. After some searching, we found that conntrack was marking in-transit connections as "new" connections (losing their state, essentially) and thus the SNAT namespace would see this as new traffic and setup a new return path. To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1620824/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
