U盘坏了，用个下面的方法安装
安装配置dhcp
yum -y install dhcp tftp-server修改如下，网段改为你自己的网段
vim /etc/dhcp/dhcpd.confsubnet 172.16.1.0 netmask 255.255.255.0 {range 172.16.1.100 172.16.1.200;option subnet-mask 255.255.255.0;default-lease-time 21600;max-lease-time 43200;next-server 172.16.1.61; #这里ip为tftp服务器的ipfilename "/pxelinux.0";
}安装httpd
yum -y install httpd
sed -i "277i ServerName 127.0.0.1:80" /etc/httpd/conf/httpd.conf挂在CentOS7 镜像
mkdir /var/www/html/CentOS-7
mount /dev/cdrom /var/www/html/CentOS-7/准备pxelinux.0文件
yum -y install syslinux
cp /usr/share/syslinux/pxelinux.0 /var/lib/tftpboot/复制isolinux所有文件至tftpboot
cp -a /var/www/html/CentOS-7/isolinux/* /var/lib/tftpboot/复制pxe配置文件
mkdir -p /var/lib/tftpboot/pxelinux.cfg
cp /var/www/html/CentOS-7/isolinux/isolinux.cfg /var/lib/tftpboot/pxelinux.cfg/default编辑pxe配置文件
vim /var/lib/tftpboot/pxelinux.cfg/defaultdefault vesamenu.c32
prompt 0
timeout 300
ONTIMEOUT localmenu title ----------------------- Install The Centos 7 Linux -----------------------------label 1
menu label ^1) Install CentOS 7 x64 kernel vmlinuzappend initrd=initrd.img method=http://172.16.1.1/CentOS-7 devfs=nomountlabel 2
menu label ^2) Install CentOS 7 x64 with VNCkernel vmlinuzappend initrd=initrd.img method=http://172.16.1.1/CentOS-7 devfs=nomount inst.vnclabel 3
menu label ^3) Auto Install CentOS 7 x64kernel vmlinuzappend initrd=initrd.img ks=http://172.16.1.1/ks/CentOS-7-ks.cfg ksdevice=em1label 4
menu label ^4) Boot from local drivelocalboot 0xffff启动服务
/etc/init.d/dhcpd start
/etc/init.d/httpd start
/etc/init.d/xinetd start
chkconfig tftp on如果选择2使用VNC方式，进入之后，访问地址在显示器上有输出,使用VNC客户端连接 IP:1 登陆安装系统
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