网络服务无法启动/重新启动时无法启动。
Restarting networking (via systemctl): networking.serviceJob for networking.service failed because the control process exited with error code.
我仍然可以通过远程控制台访问服务器，但除此之外别无他法，因为没有网络，没有出路也没有进路。
systemctl status network.service 说：
? networking.service - Raise network interfaces
Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor prese
t: enabled)
Drop-In: /run/systemd/generator/networking.service.d
??50-insserv.conf-$network.conf
Active: failed (Result: exit-code) since Mo 2016-04-18 06:53:11 UTC; 43s ago
Docs: man:interfaces(5)
Process: 3551 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=
1/FAILURE)
Process: 3546 ExecStartPre=/bin/sh -c [ "$CONFIGURE_INTERFACES" != "no" ] && [
-n "$(ifquery --read-environment --list --exclude=lo)" ] && udevadm settle …