修改完成后，重启cobblerd,然后cobbler sync做一次同步，再次新建虚拟机测试。
14.错误收集：
[root@server1 ~]# service dhcpd start
启动 dhcpd： [失败]
查看/var/log/message 看到启动dhcp的过程中发现以下错误，
Dec 9 06:19:23 server1 dhcpd: ** You must add a global ddns-update-style statement to /etc/dhcpd.conf.
Dec 9 06:19:23 server1 dhcpd: To get the same behaviour as in 3.0b2pl11 and previous
Dec 9 06:19:23 server1 dhcpd: versions, add a line that says "ddns-update-style ad-hoc;"
Dec 9 06:19:23 server1 dhcpd: Please read the dhcpd.conf manual page for more information. **
主要原因是：
文件/etc/cobbler/settings里面
manage_dhcp: 0 没有修改为1 造成的
修改为1之后，
重启cobblerd,然后做一次 cobbler sync(cobbler会把dhcp.template里面的内容复制到了/etc/dhcpd.conf)，就会自动的把dhcpd启动起来.