今天打算用VirtualBox虛擬機搭個Greenplum的集群環境，主機同意安裝CentOS 7。結果最小化按照CentOS 7后yum install 報錯，提示沒辦法連接到鏡像庫的地址，也就是沒辦法上網了。然后curl www.baidu.com提示無法查找到目標。首先想到是網絡問題，先ifconfig命令看下。結果提示未知命令，果然是最小化安裝。首先先把虛擬機的網絡設置改成橋接，保證cable connect是勾選的，然后去到/etc/sysconfig/network-scripts目錄下檢查eth0網口的設置，結果沒發現ifcfg-eth0這個文件。
先ip addr 命令查下mac地址（就是link/ether 后面那串）
然后vi /etc/sysconfig/network-scripts/ifcfg-eth0 添加eth0網口配置
保存退出執行 service network restart，結果直接報錯
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.
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 五 2017-07-14 19:01:47 CST; 1min 16s ago Docs: man:systemd-sysv-generator(8) Process: 4681 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=1/FAILURE) CGroup: /system.slice/network.service └─1192 /sbin/dhclient -H mini1 -1 -q -lf /var/lib/dhclient/dhclient--ens33.lease -pf /v... 7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists 7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists 7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists 7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists 7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists 7月 14 19:01:47 mini1 network[4681]: RTNETLINK answers: File exists 7月 14 19:01:47 mini1 systemd[1]: network.service: control process exited, code=exited status=1 7月 14 19:01:47 mini1 systemd[1]: Failed to start LSB: Bring up/down networking. 7月 14 19:01:47 mini1 systemd[1]: Unit network.service entered failed state. 7月 14 19:01:47 mini1 systemd[1]: network.service failed.
設定開機啟動一個名為NetworkManager-wait-online服務，命令為：
systemctl enable NetworkManager-wait-online.service
reboot重啟主機
重新執行systemctl status network.service就正常了。這里注意新建eth0的HWADDR后面的mac地址必須要跟本機保持一致
再運行curl baidu.com就OK了
參考：
https://www.cnblogs.com/zhizhao/p/9442487.html
http://blog.itpub.net/26506993/viewspace-2132570/