We are also affected by this suddenly after systemd upgrade the network was gone, had to go in via serial console.
We are only using networkd because Martin Pitt said in the run-up to the 16.04 release that networkd would be supported and to be used in the next LTS release. # networkctl IDX LINK TYPE OPERATIONAL SETUP 1 lo loopback carrier unmanaged 2 eth0 ether carrier configured 3 eth1 ether carrier configured 4 eth2 ether carrier configured 5 eth3 ether carrier configured 6 eth4 ether no-carrier configured 7 eth5 ether no-carrier configured 8 bond0 ether off unmanaged 9 bond1 ether routable configured 9 links listed. # head /etc/systemd/network/* -n 20 ==> /etc/systemd/network/bond1.netdev <== [NetDev] Name=bond1 Kind=bond [Bond] Mode=802.3ad MIIMonitorSec=100 TransmitHashPolicy=layer3+4 LACPTransmitRate=1 ==> /etc/systemd/network/bond1.network <== [Match] Name=bond1 [Link] MTUBytes=9000 [Network] LinkLocalAddressing=no [Network] Address=10.230.0.4/22 Gateway=10.230.0.1 ==> /etc/systemd/network/eth.network <== [Match] Name=eth* [Network] Bond=bond1 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1727301 Title: 229-4ubuntu20 added ARP option breaks existing bonding interfaces Status in systemd package in Ubuntu: Confirmed Bug description: this breaks existing configurations with bonding on upgrading from 229-4ubuntu19 to 229-4ubuntu20 on xenial as bond interfaces are now by default configured without ARP. Hence you suddenly lose network connectivity on upgrade. Very bad for a SRU. Plus adding "ARP=yes" to the Link section of a .network file does not work. Before this update, bond interfaces (specifically 802.3ad) were defaulting to ARP enabled. After the upgrade, they are created with NOARP set on the link. pre-upgrade: eth0: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> post-upgrade: eth0: <BROADCAST,MULTICAST,NOARP,SLAVE,UP,LOWER_UP> eth1: <BROADCAST,MULTICAST,NOARP,SLAVE,UP,LOWER_UP> bond0: <BROADCAST,MULTICAST,NOARP,MASTER,UP,LOWER_UP> Linux cnode11 4.4.0-97-generic #120-Ubuntu SMP Tue Sep 19 17:28:18 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1727301/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp