查看/var/log/message Jun :: root systemd: Started Network Manager.
Jun :: root systemd: Starting LSB: Bring up/down networking...
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em1: link is not ready
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em1: link is not ready
Jun :: root NetworkManager[]: <info> (em1): preparing device
Jun :: root NetworkManager[]: <info> read connection 'Wired connection 1'
Jun :: root NetworkManager[]: <info> (em1): created default wired connection 'Wired connection 1'
Jun :: root NetworkManager[]: <info> (em2): carrier is OFF
Jun :: root NetworkManager[]: <info> (em2): new Ethernet device (driver: 'tg3' ifindex: )
Jun :: root NetworkManager[]: <info> (em2): exported as /org/freedesktop/NetworkManager/Devices/
Jun :: root NetworkManager[]: <info> (em2): device state change: unmanaged -> unavailable (reason 'managed') [ ]
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em2: link is not ready
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em2: link is not ready
Jun :: root NetworkManager[]: <info> (em2): preparing device
Jun :: root NetworkManager[]: <info> (em3): carrier is OFF
Jun :: root NetworkManager[]: <info> (em3): new Ethernet device (driver: 'tg3' ifindex: )
Jun :: root NetworkManager[]: <info> (em3): exported as /org/freedesktop/NetworkManager/Devices/
Jun :: root NetworkManager[]: <info> (em3): device state change: unmanaged -> unavailable (reason 'managed') [ ]
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em3: link is not ready
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em3: link is not ready
Jun :: root NetworkManager[]: <info> (em3): preparing device
Jun :: root NetworkManager[]: <info> (em4): carrier is OFF
Jun :: root NetworkManager[]: <info> (em4): new Ethernet device (driver: 'tg3' ifindex: )
Jun :: root NetworkManager[]: <info> (em4): exported as /org/freedesktop/NetworkManager/Devices/
Jun :: root NetworkManager[]: <info> (em4): device state change: unmanaged -> unavailable (reason 'managed') [ ]
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em4: link is not ready
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): em4: link is not ready
Jun :: root NetworkManager[]: <info> (em4): preparing device
Jun :: root NetworkManager[]: <info> (p4p1): carrier is OFF
Jun :: root NetworkManager[]: <info> (p4p1): new Ethernet device (driver: 'bnx2x' ifindex: )
Jun :: root NetworkManager[]: <info> (p4p1): exported as /org/freedesktop/NetworkManager/Devices/
Jun :: root NetworkManager[]: <info> (p4p1): device state change: unmanaged -> unavailable (reason 'managed') [ ]
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): p4p1: link is not ready
Jun :: root rc.local: Unlinking stale socket /etc/supervisor.sock
Jun :: root dracut: dracut-
Jun :: root kernel: bnx2x ::00.0 p4p1: using MSI-X IRQs: sp fp[] ... fp[]
Jun :: root dracut: Executing: /usr/sbin/dracut --hostonly --hostonly-cmdline -o "plymouth dash resume" -f /boot/initramfs-3.10.-.el7.x86_64kdump.img 3.10.-.el7.x86_64
Jun :: root systemd: Started Dynamic System Tuning Daemon.
Jun :: root rc.local: SIOCADDRT: Network is unreachable
Jun :: root kernel: IPv6: ADDRCONF(NETDEV_UP): p4p1: link is not ready
Jun :: root NetworkManager[]: <info> (p4p1): preparing device
Jun :: root NetworkManager[]: <info> (p4p2): carrier is OFF
Jun :: root NetworkManager[]: <info> (p4p2): new Ethernet device (driver: 'bnx2x' ifindex: )
Jun :: root NetworkManager[]: <info> (p4p2): exported as /org/freedesktop/NetworkManager/Devices/
Jun :: root NetworkManager[]: <info> (p4p2): device state change: unmanaged -> unavailable (reason 'managed') [ ]
Jun :: root rc.local: SIOCADDRT: Network is unreachable
Jun :: root systemd: rc-local.service: control process exited, code=exited status=
Jun :: root systemd: Failed to start /etc/rc.d/rc.local Compatibility.
Jun :: root systemd: Unit rc-local.service entered failed state.
打开/etc/rc.local看是否有其它的任务或者开关导致启动失败。如果有就看需要去除