Centos7出现异常：Failed to start LSB: Bring up/down networking.
按照《Kafka：ZK+Kafka+Spark Streaming集群环境搭建（一）VMW安装四台CentOS，并实现本机与它们能交互，虚拟机内部实现可以上网。》配置好虚拟机，正在使用中，让它强制断电后，启动起来发现ip无法访问，而且重启网络失败：
执行：systemctl restart network.service 出现异常：Failed to start LSB: Bring up/down networking.
执行ifconfig，发现配置好的ens33也不见了：
[spark@master ~]$ ifconfig lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 4 bytes 336 (336.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4 bytes 336 (336.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
解决方案：
systemctl stop NetworkManager 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.
重新启动网络：
systemctl start network.service
重新ifconfig查看是否ens33启用
[root@master spark]# ifconfig ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.0.120 netmask 255.255.255.0 broadcast 192.168.0.255 inet6 fe80::20c:29ff:fe71:ac74 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:71:ac:74 txqueuelen 1000 (Ethernet) RX packets 235 bytes 28303 (27.6 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 137 bytes 22067 (21.5 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 4 bytes 336 (336.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4 bytes 336 (336.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 [root@master spark]#
到此ens33起作用了，此时测试网络也可以通了。