2018-04-11 NetworkManager state is now DISCONNECTED

NetworkManager 导致 服务器网络频繁短时间中断，内核日志如下：

Apr 11 10:20:59 localhost systemd: Starting Session 14 of user root.
Apr 11 10:20:59 localhost dbus-daemon: dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:20:59 localhost dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:20:59 localhost dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:20:59 localhost dbus-daemon: dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4586] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4591] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:21:16 localhost NetworkManager[976]: <warn>  [1523413276.4597] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4608] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4649] policy: auto-activating connection 'ens3f0'
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4681] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4685] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4687] manager: NetworkManager state is now CONNECTING
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4695] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:21:16 localhost NetworkManager[976]: <info>  [1523413276.4705] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4567] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4571] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:21:48 localhost NetworkManager[976]: <warn>  [1523413308.4573] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4580] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4600] policy: auto-activating connection 'ens3f0'
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4608] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4609] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4611] manager: NetworkManager state is now CONNECTING
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4613] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:21:48 localhost NetworkManager[976]: <info>  [1523413308.4618] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:21:48 localhost su: (to root) root on none
Apr 11 10:21:48 localhost systemd: Started Session c8 of user root.
Apr 11 10:21:48 localhost systemd: Starting Session c8 of user root.
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4658] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4661] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:22:20 localhost NetworkManager[976]: <warn>  [1523413340.4663] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4671] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4690] policy: auto-activating connection 'ens3f0'
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4701] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4703] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4704] manager: NetworkManager state is now CONNECTING
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4710] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:22:20 localhost NetworkManager[976]: <info>  [1523413340.4713] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:22:52 localhost NetworkManager[976]: <info>  [1523413372.4656] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:22:52 localhost NetworkManager[976]: <info>  [1523413372.4660] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:22:52 localhost NetworkManager[976]: <info>  [1523413372.4661] policy: disabling autoconnect for connection 'ens3f0'.
Apr 11 10:22:52 localhost NetworkManager[976]: <warn>  [1523413372.4664] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:22:52 localhost NetworkManager[976]: <info>  [1523413372.4679] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:27:52 localhost NetworkManager[976]: <info>  [1523413672.4746] policy: auto-activating connection 'ens3f0'
Apr 11 10:27:52 localhost NetworkManager[976]: <info>  [1523413672.4763] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:27:52 localhost NetworkManager[976]: <info>  [1523413672.4767] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:27:52 localhost NetworkManager[976]: <info>  [1523413672.4769] manager: NetworkManager state is now CONNECTING
Apr 11 10:27:52 localhost NetworkManager[976]: <info>  [1523413672.4776] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:27:52 localhost NetworkManager[976]: <info>  [1523413672.4784] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:27:53 localhost systemd-logind: New session 15 of user root.
Apr 11 10:27:53 localhost systemd: Started Session 15 of user root.
Apr 11 10:27:53 localhost systemd: Starting Session 15 of user root.
Apr 11 10:27:53 localhost dbus-daemon: dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:27:53 localhost dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:27:53 localhost dbus-daemon: dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:27:53 localhost dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4576] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4580] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:28:24 localhost NetworkManager[976]: <warn>  [1523413704.4584] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4590] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4618] policy: auto-activating connection 'ens3f0'
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4630] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4633] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4634] manager: NetworkManager state is now CONNECTING
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4639] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:28:24 localhost NetworkManager[976]: <info>  [1523413704.4645] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4455] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4459] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:28:56 localhost NetworkManager[976]: <warn>  [1523413736.4461] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4474] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4498] policy: auto-activating connection 'ens3f0'
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4507] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4509] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4510] manager: NetworkManager state is now CONNECTING
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4514] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:28:56 localhost NetworkManager[976]: <info>  [1523413736.4519] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:29:09 localhost systemd-logind: New session 16 of user root.
Apr 11 10:29:09 localhost systemd: Started Session 16 of user root.
Apr 11 10:29:09 localhost systemd: Starting Session 16 of user root.
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4481] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4488] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:29:28 localhost NetworkManager[976]: <warn>  [1523413768.4493] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4501] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4539] policy: auto-activating connection 'ens3f0'
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4557] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4560] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4562] manager: NetworkManager state is now CONNECTING
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4568] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:29:28 localhost NetworkManager[976]: <info>  [1523413768.4575] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:29:33 localhost su: (to root) root on none
Apr 11 10:29:33 localhost systemd: Started Session c9 of user root.
Apr 11 10:29:33 localhost systemd: Starting Session c9 of user root.
Apr 11 10:30:00 localhost NetworkManager[976]: <info>  [1523413800.4645] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:30:00 localhost NetworkManager[976]: <info>  [1523413800.4650] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:30:00 localhost NetworkManager[976]: <info>  [1523413800.4652] policy: disabling autoconnect for connection 'ens3f0'.
Apr 11 10:30:00 localhost NetworkManager[976]: <warn>  [1523413800.4654] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:30:00 localhost NetworkManager[976]: <info>  [1523413800.4659] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:30:01 localhost systemd: Started Session 17 of user root.
Apr 11 10:30:01 localhost systemd: Starting Session 17 of user root.
Apr 11 10:35:00 localhost NetworkManager[976]: <info>  [1523414100.4907] policy: auto-activating connection 'ens3f0'
Apr 11 10:35:00 localhost NetworkManager[976]: <info>  [1523414100.4925] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:35:00 localhost NetworkManager[976]: <info>  [1523414100.4928] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:35:00 localhost NetworkManager[976]: <info>  [1523414100.4932] manager: NetworkManager state is now CONNECTING
Apr 11 10:35:00 localhost NetworkManager[976]: <info>  [1523414100.4939] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:35:00 localhost NetworkManager[976]: <info>  [1523414100.4949] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:35:12 localhost systemd-logind: New session 18 of user root.
Apr 11 10:35:12 localhost systemd: Started Session 18 of user root.
Apr 11 10:35:12 localhost systemd: Starting Session 18 of user root.
Apr 11 10:35:13 localhost dbus-daemon: dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:35:13 localhost dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:35:13 localhost dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:35:13 localhost dbus-daemon: dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:35:18 localhost systemd: Started Session 19 of user root.
Apr 11 10:35:18 localhost systemd-logind: New session 19 of user root.
Apr 11 10:35:18 localhost systemd: Starting Session 19 of user root.
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4445] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4449] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:35:32 localhost NetworkManager[976]: <warn>  [1523414132.4453] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4462] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4493] policy: auto-activating connection 'ens3f0'
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4504] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4506] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4508] manager: NetworkManager state is now CONNECTING
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4513] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:35:32 localhost NetworkManager[976]: <info>  [1523414132.4517] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4606] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4609] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:36:04 localhost NetworkManager[976]: <warn>  [1523414164.4613] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4618] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4643] policy: auto-activating connection 'ens3f0'
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4655] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4657] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4658] manager: NetworkManager state is now CONNECTING
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4662] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:36:04 localhost NetworkManager[976]: <info>  [1523414164.4673] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:36:28 localhost systemd-logind: New session 20 of user root.
Apr 11 10:36:28 localhost systemd: Started Session 20 of user root.
Apr 11 10:36:28 localhost systemd: Starting Session 20 of user root.
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4444] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4448] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:36:35 localhost NetworkManager[976]: <warn>  [1523414195.4451] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4461] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4486] policy: auto-activating connection 'ens3f0'
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4497] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4499] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4501] manager: NetworkManager state is now CONNECTING
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4504] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:36:35 localhost NetworkManager[976]: <info>  [1523414195.4509] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:37:07 localhost NetworkManager[976]: <info>  [1523414227.4658] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:37:07 localhost NetworkManager[976]: <info>  [1523414227.4662] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:37:07 localhost NetworkManager[976]: <info>  [1523414227.4663] policy: disabling autoconnect for connection 'ens3f0'.
Apr 11 10:37:07 localhost NetworkManager[976]: <warn>  [1523414227.4667] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:37:07 localhost NetworkManager[976]: <info>  [1523414227.4672] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:37:48 localhost systemd-logind: Removed session 11.
Apr 11 10:40:01 localhost systemd: Started Session 21 of user root.
Apr 11 10:40:01 localhost systemd: Starting Session 21 of user root.
Apr 11 10:42:07 localhost NetworkManager[976]: <info>  [1523414527.5443] policy: auto-activating connection 'ens3f0'
Apr 11 10:42:07 localhost NetworkManager[976]: <info>  [1523414527.5460] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:42:07 localhost NetworkManager[976]: <info>  [1523414527.5464] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:42:07 localhost NetworkManager[976]: <info>  [1523414527.5467] manager: NetworkManager state is now CONNECTING
Apr 11 10:42:07 localhost NetworkManager[976]: <info>  [1523414527.5473] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:42:07 localhost NetworkManager[976]: <info>  [1523414527.5483] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:42:16 localhost systemd-logind: New session 22 of user root.
Apr 11 10:42:16 localhost systemd: Started Session 22 of user root.
Apr 11 10:42:16 localhost systemd: Starting Session 22 of user root.
Apr 11 10:42:16 localhost dbus-daemon: dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:42:16 localhost dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:42:16 localhost dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:42:16 localhost dbus-daemon: dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:42:16 localhost systemd-logind: New session 23 of user root.
Apr 11 10:42:16 localhost systemd: Started Session 23 of user root.
Apr 11 10:42:16 localhost systemd: Starting Session 23 of user root.
Apr 11 10:42:18 localhost systemd-logind: New session 24 of user root.
Apr 11 10:42:18 localhost systemd: Started Session 24 of user root.
Apr 11 10:42:18 localhost systemd: Starting Session 24 of user root.
Apr 11 10:42:39 localhost systemd: Reloading.
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4652] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4658] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:42:39 localhost NetworkManager[976]: <warn>  [1523414559.4668] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4672] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4693] policy: auto-activating connection 'ens3f0'
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4701] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4703] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4704] manager: NetworkManager state is now CONNECTING
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4706] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:42:39 localhost NetworkManager[976]: <info>  [1523414559.4711] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:42:48 localhost su: (to root) root on none
Apr 11 10:42:48 localhost systemd: Started Session c10 of user root.
Apr 11 10:42:48 localhost systemd: Starting Session c10 of user root.
Apr 11 10:43:11 localhost systemd: Reloading.
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4662] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4667] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:43:11 localhost NetworkManager[976]: <warn>  [1523414591.4672] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4678] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4699] policy: auto-activating connection 'ens3f0'
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4708] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4709] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4710] manager: NetworkManager state is now CONNECTING
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4713] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:43:11 localhost NetworkManager[976]: <info>  [1523414591.4716] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:43:30 localhost systemd: Reloading.
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4657] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4662] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:43:43 localhost NetworkManager[976]: <warn>  [1523414623.4669] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4678] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4710] policy: auto-activating connection 'ens3f0'
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4719] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4722] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4723] manager: NetworkManager state is now CONNECTING
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4727] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:43:43 localhost NetworkManager[976]: <info>  [1523414623.4732] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:44:15 localhost NetworkManager[976]: <info>  [1523414655.4665] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:44:15 localhost NetworkManager[976]: <info>  [1523414655.4670] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:44:15 localhost NetworkManager[976]: <info>  [1523414655.4672] policy: disabling autoconnect for connection 'ens3f0'.
Apr 11 10:44:15 localhost NetworkManager[976]: <warn>  [1523414655.4676] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:44:15 localhost NetworkManager[976]: <info>  [1523414655.4683] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:44:41 localhost systemd-logind: Removed session 14.
Apr 11 10:49:15 localhost NetworkManager[976]: <info>  [1523414955.5446] policy: auto-activating connection 'ens3f0'
Apr 11 10:49:15 localhost NetworkManager[976]: <info>  [1523414955.5463] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:49:15 localhost NetworkManager[976]: <info>  [1523414955.5466] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:49:15 localhost NetworkManager[976]: <info>  [1523414955.5469] manager: NetworkManager state is now CONNECTING
Apr 11 10:49:15 localhost NetworkManager[976]: <info>  [1523414955.5475] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:49:15 localhost NetworkManager[976]: <info>  [1523414955.5484] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:49:18 localhost systemd-logind: New session 25 of user root.
Apr 11 10:49:18 localhost systemd: Started Session 25 of user root.
Apr 11 10:49:18 localhost systemd: Starting Session 25 of user root.
Apr 11 10:49:18 localhost dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:49:18 localhost dbus-daemon: dbus[962]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 11 10:49:18 localhost dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:49:18 localhost dbus-daemon: dbus[962]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4657] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4662] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:49:47 localhost NetworkManager[976]: <warn>  [1523414987.4668] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4677] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4717] policy: auto-activating connection 'ens3f0'
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4734] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4738] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4740] manager: NetworkManager state is now CONNECTING
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4747] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:49:47 localhost NetworkManager[976]: <info>  [1523414987.4754] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:50:01 localhost systemd: Started Session 26 of user root.
Apr 11 10:50:01 localhost systemd: Starting Session 26 of user root.
Apr 11 10:50:15 localhost su: (to root) root on none
Apr 11 10:50:15 localhost systemd: Started Session c11 of user root.
Apr 11 10:50:15 localhost systemd: Starting Session c11 of user root.
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4473] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4478] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:50:19 localhost NetworkManager[976]: <warn>  [1523415019.4483] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4491] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4529] policy: auto-activating connection 'ens3f0'
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4546] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4549] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4552] manager: NetworkManager state is now CONNECTING
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4558] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:50:19 localhost NetworkManager[976]: <info>  [1523415019.4564] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:50:27 localhost su: (to root) root on none
Apr 11 10:50:27 localhost systemd: Started Session c12 of user root.
Apr 11 10:50:27 localhost systemd: Starting Session c12 of user root.
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4456] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4462] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:50:51 localhost NetworkManager[976]: <warn>  [1523415051.4467] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4476] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4517] policy: auto-activating connection 'ens3f0'
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4534] device (ens3f0): Activation: starting connection 'ens3f0' (8324c727-b3b8-4266-b45f-dc8c58d0fa0b)
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4538] device (ens3f0): state change: disconnected -> prepare (reason 'none') [30 40 0]
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4541] manager: NetworkManager state is now CONNECTING
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4547] device (ens3f0): state change: prepare -> config (reason 'none') [40 50 0]
Apr 11 10:50:51 localhost NetworkManager[976]: <info>  [1523415051.4554] device (ens3f0): state change: config -> ip-config (reason 'none') [50 70 0]
Apr 11 10:51:23 localhost NetworkManager[976]: <info>  [1523415083.4664] device (ens3f0): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Apr 11 10:51:23 localhost NetworkManager[976]: <info>  [1523415083.4669] manager: NetworkManager state is now DISCONNECTED
Apr 11 10:51:23 localhost NetworkManager[976]: <info>  [1523415083.4671] policy: disabling autoconnect for connection 'ens3f0'.
Apr 11 10:51:23 localhost NetworkManager[976]: <warn>  [1523415083.4674] device (ens3f0): Activation: failed for connection 'ens3f0'
Apr 11 10:51:23 localhost NetworkManager[976]: <info>  [1523415083.4682] device (ens3f0): state change: failed -> disconnected (reason 'none') [120 30 0]
Apr 11 10:52:06 localhost systemd-logind: Removed session 15.

尼玛，服务器断6分钟，好1分钟，开始我还以为服务器在重启，我刚刚修改了服务器打开文件数量限制，是动了内核参数，但是查看top 与 uptime 命令发现服务器并没有重启坑死人了要。经过查找内核日志并 Google，终于找到了方法：

解决办法如下，前提：我使用的服务器是静态ip，根本不需要这个鬼 NetworkManager，符合下面条件，借鉴之前请自行甄别：

Such thing happens when eth1 is not configured but the system service NetworkManager is trying to get a configuration using dhclient.

So you may stop and disable NetworkManager (commonly, we do not need it on the server):

systemctl stop NetworkManager  
systemctl disable NetworkManager