Public bug reported: I have a tenant network attached to a router and external network, and some VMs with Floating IPs deployed. I updated the network MTU from 1500 to 1300 (just as a test, but try any other MTU), and restarted nova compute, ovs agent, l3-agent.
All interfaces (qvo/qvb/qbr, qr, dhcp taps, sg, fg, qg) got updated except for the rfp-fpr peer link between qrouter and fip namespace: [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ifconfig | grep mtu br-ex: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens32: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens35: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens34.1801: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 qbr05d85481-ca: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qbr147c3499-25: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qbrbf9399bf-17: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qbrf1ba8ee0-e1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qvb05d85481-ca: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvb147c3499-25: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvbbf9399bf-17: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvbf1ba8ee0-e1: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvo05d85481-ca: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvo147c3499-25: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvobf9399bf-17: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvof1ba8ee0-e1: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 tap05d85481-ca: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 tap147c3499-25: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 tapbf9399bf-17: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 tapf1ba8ee0-e1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec qrouter-b57abb6d-92ff-4ebd-a71f-6b26646eddfa ifconfig | grep mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 qr-9f725d28-82: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qr-a9852f10-d1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 rfp-b57abb6d-9: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec qdhcp-ada1b967-9604-42ea-88bc-d887ce3e877e ifconfig | grep mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 tap8ecd0a51-63: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec fip-4ff6386b-c547-465e-a734-49eed1ae6832 ifconfig | grep mtu fg-a7668bc9-97: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 fpr-b57abb6d-9: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec snat-b57abb6d-92ff-4ebd-a71f-6b26646eddfa ifconfig | grep mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 qg-d69632ce-e4: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 sg-83643ed0-34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 sg-9eac9eee-69: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 VM taps are still at 1500, but will change if I powercycle VMs or migrate. rfp/fprs remain at 1500 and unsure of how to get their MTUs to update ** Affects: neutron Importance: Undecided Status: New ** Tags: l3-dvr-backlog -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. https://bugs.launchpad.net/bugs/1823798 Title: rfp and fpr interfaces not updated after changing network MTU Status in neutron: New Bug description: I have a tenant network attached to a router and external network, and some VMs with Floating IPs deployed. I updated the network MTU from 1500 to 1300 (just as a test, but try any other MTU), and restarted nova compute, ovs agent, l3-agent. All interfaces (qvo/qvb/qbr, qr, dhcp taps, sg, fg, qg) got updated except for the rfp-fpr peer link between qrouter and fip namespace: [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ifconfig | grep mtu br-ex: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens32: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens35: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ens34.1801: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 qbr05d85481-ca: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qbr147c3499-25: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qbrbf9399bf-17: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qbrf1ba8ee0-e1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qvb05d85481-ca: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvb147c3499-25: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvbbf9399bf-17: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvbf1ba8ee0-e1: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvo05d85481-ca: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvo147c3499-25: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvobf9399bf-17: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 qvof1ba8ee0-e1: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST> mtu 1300 tap05d85481-ca: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 tap147c3499-25: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 tapbf9399bf-17: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 tapf1ba8ee0-e1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec qrouter-b57abb6d-92ff-4ebd-a71f-6b26646eddfa ifconfig | grep mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 qr-9f725d28-82: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 qr-a9852f10-d1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 rfp-b57abb6d-9: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec qdhcp-ada1b967-9604-42ea-88bc-d887ce3e877e ifconfig | grep mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 tap8ecd0a51-63: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec fip-4ff6386b-c547-465e-a734-49eed1ae6832 ifconfig | grep mtu fg-a7668bc9-97: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 fpr-b57abb6d-9: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 [root@dvr-tn-vl-c7-10-4-211-218platform9 ~]# ip netns exec snat-b57abb6d-92ff-4ebd-a71f-6b26646eddfa ifconfig | grep mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 qg-d69632ce-e4: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 sg-83643ed0-34: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 sg-9eac9eee-69: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1300 VM taps are still at 1500, but will change if I powercycle VMs or migrate. rfp/fprs remain at 1500 and unsure of how to get their MTUs to update To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1823798/+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