We are seeing a ton of errors and warnings from NetworkManager in /var/log/messages, about every minute or so. Everything seems to be operating nicely other than these messages. This is a CentOS 7 host running Docker 1.11.0.
What is causing these?
Jun 6 09:10:58 dockerhost NetworkManager[919]: <warn> (vethd9692e3): failed to disable userspace IPv6LL address handling
Jun 6 09:10:58 dockerhost NetworkManager[919]: <info> (docker0): bridge port veth711172c was detached
Jun 6 09:10:58 dockerhost NetworkManager[919]: <info> (veth711172c): released from master docker0
Jun 6 09:10:58 dockerhost NetworkManager[919]: <warn> (veth711172c): failed to disable userspace IPv6LL address handling
Jun 6 09:11:28 dockerhost kernel: [1556517.993974] XFS (dm-18): Mounting V4 Filesystem
Jun 6 09:11:28 dockerhost kernel: [1556518.247653] XFS (dm-18): Ending clean mount
Jun 6 09:11:28 dockerhost NetworkManager[919]: <warn> (veth3773231): failed to find device 48794 'veth3773231' with udev
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth3773231): new Veth device (carrier: OFF, driver: 'veth', ifindex: 48794)
Jun 6 09:11:28 dockerhost NetworkManager[919]: <warn> (veth5149103): failed to find device 48795 'veth5149103' with udev
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): new Veth device (carrier: OFF, driver: 'veth', ifindex: 48795)
Jun 6 09:11:28 dockerhost kernel: [1556518.270063] device veth5149103 entered promiscuous mode
Jun 6 09:11:28 dockerhost kernel: [1556518.278810] IPv6: ADDRCONF(NETDEV_UP): veth5149103: link is not ready
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (docker0): bridge port veth5149103 was attached
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): enslaved to docker0
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> ifcfg-rh: add connection in-memory (a26fd6c5-558d-4a5a-8474-683faed6854d,"veth5149103")
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: unmanaged -> unavailable (reason 'connection-assumed') [10 20 41]
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: unavailable -> disconnected (reason 'connection-assumed') [20 30 41]
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): Activation: starting connection 'veth5149103' (a26fd6c5-558d-4a5a-8474-683faed6854d)
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: disconnected -> prepare (reason 'none') [30 40 0]
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: prepare -> config (reason 'none') [40 50 0]
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: config -> ip-config (reason 'none') [50 70 0]
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: ip-config -> secondaries (reason 'none') [70 90 0]
Jun 6 09:11:28 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: secondaries -> activated (reason 'none') [90 100 0]
Jun 6 09:11:29 dockerhost kernel: [1556518.567888] IPv6: ADDRCONF(NETDEV_CHANGE): veth5149103: link becomes ready
Jun 6 09:11:29 dockerhost kernel: [1556518.568006] docker0: port 14(veth5149103) entered forwarding state
Jun 6 09:11:29 dockerhost kernel: [1556518.568016] docker0: port 14(veth5149103) entered forwarding state
Jun 6 09:11:29 dockerhost NetworkManager[919]: <info> (veth5149103): Activation: successful, device activated.
Jun 6 09:11:29 dockerhost NetworkManager[919]: <warn> (veth3773231): failed to disable userspace IPv6LL address handling
Jun 6 09:11:29 dockerhost NetworkManager[919]: <info> (veth5149103): link connected
Jun 6 09:11:29 dockerhost dbus[893]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
Jun 6 09:11:29 dockerhost dbus[893]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Jun 6 09:11:29 dockerhost nm-dispatcher: Dispatching action 'up' for veth5149103
Jun 6 09:11:29 dockerhost kernel: [1556518.968662] docker0: port 14(veth5149103) entered disabled state
Jun 6 09:11:29 dockerhost NetworkManager[919]: <warn> (veth3773231): failed to find device 48794 'veth3773231' with udev
Jun 6 09:11:29 dockerhost NetworkManager[919]: <info> (veth3773231): new Veth device (carrier: OFF, driver: 'veth', ifindex: 48794)
Jun 6 09:11:29 dockerhost kernel: [1556519.085382] docker0: port 14(veth5149103) entered disabled state
Jun 6 09:11:29 dockerhost kernel: [1556519.093163] device veth5149103 left promiscuous mode
Jun 6 09:11:29 dockerhost kernel: [1556519.093185] docker0: port 14(veth5149103) entered disabled state
Jun 6 09:11:29 dockerhost NetworkManager[919]: <info> (veth5149103): link disconnected (deferring action for 4 seconds)
Jun 6 09:11:29 dockerhost NetworkManager[919]: <warn> (veth3773231): failed to disable userspace IPv6LL address handling
Jun 6 09:11:29 dockerhost NetworkManager[919]: <info> (veth5149103): device state change: activated -> unmanaged (reason 'removed') [100 10 36]