Red Hat Bugzilla – Bug 1364275
Unable to set up mtu on bonded interface in RHEL 7.2
Last modified: 2016-11-03 15:27:58 EDT
ISSUE: ====== - Unable to set MTU on bond device. - Already running newer NetworkManager release below based on: https://access.redhat.com/solutions/1309583 RUNNING: NetworkManager-1.0.6-30.el7_2.x86_64 RECOMMENDED: NetworkManager-1.0.6-27.el7 or later - Adjusting the MTU manually appears to work: [root@newanaly ~]# ip link set dev bond0 mtu 9000 [root@newanaly ~]# ip link set dev vlan53 mtu 9000 REPRODUCTION/TESTING: ===================== Seems this is a bug. I only could set the MTU if I add a "BOOTPROTO=dhcp" on ifcfg-bond0. # grep "MTU\|BOOTPROTO" /etc/sysconfig/network-scripts/ifcfg-bond* /etc/sysconfig/network-scripts/ifcfg-bond0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth1:MTU="9000" # for dev in eth0 eth1 bond0; do ip l show dev $dev; done 2: eth0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff 3: eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff 7: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff # echo "BOOTPROTO=dhcp" >> /etc/sysconfig/network-scripts/ifcfg-bond0 # reboot # for dev in eth0 eth1 bond0; do ip l show dev $dev; done 2: eth0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast master bond0 state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff 3: eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast master bond0 state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff 7: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP mode DEFAULT link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff # grep "MTU\|BOOTPROTO" /etc/sysconfig/network-scripts/ifcfg-bond* /etc/sysconfig/network-scripts/ifcfg-bond0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond0:BOOTPROTO=dhcp /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth1:MTU="9000" And the "BOOTPROTO" must be "dhcp" or "static". --- As 'dhcp': # sed -i "s/^BOOTPROTO=.*$/BOOTPROTO=none/g" /etc/sysconfig/network-scripts/ifcfg-bond0 # grep "MTU\|BOOTPROTO" /etc/sysconfig/network-scripts/ifcfg-bond* /etc/sysconfig/network-scripts/ifcfg-bond0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond0:BOOTPROTO=none /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth1:MTU="9000" # reboot # for dev in eth0 eth1 bond0; do ip l show dev $dev; done 2: eth0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:1a:bb:9f brd ff:ff:ff:ff:ff:ff 3: eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:1a:bb:9f brd ff:ff:ff:ff:ff:ff 7: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT link/ether 00:16:3e:1a:bb:9f brd ff:ff:ff:ff:ff:ff --- As 'static' is not necessary set a IP address. The MTU of the bond0 is configured as 9000, but the devices eth0 and eth1 are not configured. # sed -i "s/^BOOTPROTO=.*$/BOOTPROTO=static/g" /etc/sysconfig/network-scripts/ifcfg-bond0 # reboot # grep "MTU\|BOOTPROTO" /etc/sysconfig/network-scripts/ifcfg-bond* /etc/sysconfig/network-scripts/ifcfg-bond0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond0:BOOTPROTO=static /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth0:MTU="9000" /etc/sysconfig/network-scripts/ifcfg-bond-slave-eth1:MTU="9000" # for dev in eth0 eth1 bond0; do ip l show dev $dev; done 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:1a:bb:9f brd ff:ff:ff:ff:ff:ff 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000 link/ether 00:16:3e:31:c5:0f brd ff:ff:ff:ff:ff:ff 7: bond0: <NO-CARRIER,BROADCAST,MULTICAST,MASTER,UP> mtu 9000 qdisc noqueue state DOWN mode DEFAULT link/ether 9e:c8:27:9d:f2:3e brd ff:ff:ff:ff:ff:ff
Tried on RHEL 7.3, NetworkManager-1.4.0-0.4.git20160727.9446481f.el7, the bond and vlan interfaces get the correct MTU: 6: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP mode DEFAULT qlen 1000 link/ether 52:54:00:a4:80:fb brd ff:ff:ff:ff:ff:ff 7: vlan53@bond0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc noqueue state UP mode DEFAULT qlen 1000 link/ether 52:54:00:a4:80:fb brd ff:ff:ff:ff:ff:ff The issue was fixed by commit [1] for bug 1303968, which is quite similar to this. But probably it's wise not to close this as duplicate so the different scenario (bond + vlan) gets tested by QE as well. [1] https://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?id=53dfaddda2adad15f4fbf35780bc03503cc45a63
mtu can be set correctly to bridged bond
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2016-2581.html