CentOS 7 下网络无法访问 Failed to start LSB: Bring up/.

[root@localhost Desktop]# ping 192.168.2.1
PING 192.168.2.1 (192.168.2.1) 56(84) bytes of data.
64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=0.067 ms
64 bytes from 192.168.2.1: icmp_seq=2 ttl=64 time=0.065 ms
64 bytes from 192.168.2.1: icmp_seq=3 ttl=64 time=0.079 ms
^C
--- 192.168.2.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2006ms
rtt min/avg/max/mdev = 0.065/0.070/0.079/0.009 ms
[root@localhost Desktop]# ping www.baidu.com
ping: unknown host www.baidu.com
[root@localhost Desktop]# route add default gw 192.168.2.1
[root@localhost Desktop]# service network restart
Restarting network (via systemctl): Job for network.service failed because the control process exited with error code. See "systemctl status network.service" and "journalctl -xe" for details.
[FAILED]
[root@localhost Desktop]# systemctl status network.service
● network.service - LSB: Bring up/down networking
Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2017-08-17 19:13:34 PDT; 2min 13s ago
Docs: man:systemd-sysv-generator(8)
Process: 3688 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE)

Aug 17 19:13:34 localhost.localdomain network[3688]: RTNETLINK answers: File exists
Aug 17 19:13:34 localhost.localdomain network[3688]: RTNETLINK answers: File exists
Aug 17 19:13:34 localhost.localdomain network[3688]: RTNETLINK answers: File exists
Aug 17 19:13:34 localhost.localdomain network[3688]: RTNETLINK answers: File exists
Aug 17 19:13:34 localhost.localdomain network[3688]: RTNETLINK answers: File exists
Aug 17 19:13:34 localhost.localdomain network[3688]: RTNETLINK answers: File exists
Aug 17 19:13:34 localhost.localdomain systemd[1]: network.service: control proce...1
Aug 17 19:13:34 localhost.localdomain systemd[1]: Failed to start LSB: Bring up/....
Aug 17 19:13:34 localhost.localdomain systemd[1]: Unit network.service entered f....
Aug 17 19:13:34 localhost.localdomain systemd[1]: network.service failed.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost Desktop]# clear

[root@localhost Desktop]# systemctl stop NetworkManager
[root@localhost Desktop]# systemctl disable NetworkManager
Removed symlink /etc/systemd/system/multi-user.target.wants/NetworkManager.service.
Removed symlink /etc/systemd/system/dbus-org.freedesktop.NetworkManager.service.
Removed symlink /etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service.
[root@localhost Desktop]# systemctl start network.service
[root@localhost Desktop]# ping www.baidu.com
PING www.a.shifen.com (111.13.100.91) 56(84) bytes of data.
64 bytes from 111.13.100.91: icmp_seq=1 ttl=51 time=20.8 ms
64 bytes from 111.13.100.91: icmp_seq=2 ttl=51 time=21.0 ms
64 bytes from 111.13.100.91: icmp_seq=3 ttl=51 time=22.2 ms
64 bytes from 111.13.100.91: icmp_seq=4 ttl=51 time=21.6 ms
64 bytes from 111.13.100.91: icmp_seq=5 ttl=51 time=21.6 ms
64 bytes from 111.13.100.91: icmp_seq=6 ttl=51 time=21.4 ms
64 bytes from 111.13.100.91: icmp_seq=7 ttl=51 time=21.2 ms
64 bytes from 111.13.100.91: icmp_seq=8 ttl=51 time=21.7 ms
64 bytes from 111.13.100.91: icmp_seq=9 ttl=51 time=52.0 ms
64 bytes from 111.13.100.91: icmp_seq=10 ttl=50 time=26.7 ms
64 bytes from 111.13.100.91: icmp_seq=11 ttl=50 time=24.9 ms
64 bytes from 111.13.100.91: icmp_seq=12 ttl=50 time=22.9 ms
64 bytes from 111.13.100.91: icmp_seq=13 ttl=50 time=27.9 ms
64 bytes from 111.13.100.91: icmp_seq=14 ttl=50 time=45.3 ms
64 bytes from 111.13.100.91: icmp_seq=15 ttl=50 time=54.8 ms
64 bytes from 111.13.100.91: icmp_seq=16 ttl=50 time=51.8 ms
64 bytes from 111.13.100.91: icmp_seq=17 ttl=50 time=32.6 ms
64 bytes from 111.13.100.91: icmp_seq=18 ttl=50 time=22.2 ms
64 bytes from 111.13.100.91: icmp_seq=19 ttl=50 time=22.9 ms
64 bytes from 111.13.100.91: icmp_seq=20 ttl=50 time=25.4 ms
64 bytes from 111.13.100.91: icmp_seq=21 ttl=50 time=23.0 ms
64 bytes from 111.13.100.91: icmp_seq=22 ttl=50 time=30.3 ms
64 bytes from 111.13.100.91: icmp_seq=23 ttl=50 time=25.2 ms
^C64 bytes from 111.13.100.91: icmp_seq=24 ttl=50 time=33.6 ms

--- www.a.shifen.com ping statistics ---
24 packets transmitted, 24 received, 0% packet loss, time 222495ms
rtt min/avg/max/mdev = 20.851/28.921/54.831/10.573 ms
You have new mail in /var/spool/mail/root
[root@localhost Desktop]#