前言：
对于单台服务器上的OS安装，我们可以手动进行，若是一个集群服务中的多个节点超过50台服务器的OS安装，手动安装显然是不可行的，因此作为系统运维工程师自动化运维是我们必不可缺的技能。
PXE是一种引导协议，它通过网络来启动系统安装过程。
一、环境准备
在Centos6 操作系统上实现PXE的自动化部署OS，所依赖的服务有：dhcp, tftp, fileserver(http,ftp,nfs)，依赖的安装源:kickstart文件，可引导内核-vimlinuz,initrd.img文件。
PXE自动化部署OS拓扑图
节点准备：节点zly准备两块网卡，将网卡eth0做外接网卡，将第二块网卡eth1做PXE完成自动化部署OS，网卡eth0桥接模式，网卡eth1内网模式vmnet2；
[root@ zly ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth1DEVICE=eth1BOOTPROTO=staticONBOOT=yesIPADDR=192.168.20.3NETMASK=255.255.255.0GATEWAY=192.168.20.3HWADDR=00:0C:29:73:9F:1B..................[root@ zly ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:73:9F:11 inet addr:172.16.20.8 Bcast:172.16.255.255 Mask:255.255.0.0 inet6 addr: fe80::20c:29ff:fe73:9f11/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:12463 errors:0 dropped:0 overruns:0 frame:0 TX packets:6010 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:11748882 (11.2 MiB) TX bytes:515051 (502.9 KiB)eth1 Link encap:Ethernet HWaddr 00:0C:29:73:9F:1B inet addr:192.168.20.3 Bcast:192.168.20.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fe73:9f1b/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:468 (468.0 b)[root@ zly ~]# service network restart
二、下载镜像光盘至本地准备PXE所依赖的安装源
1、下载光盘镜像，并查看所需要的文件；
[root@zly ~]# lftp http://172.16.0.1/cobbler/ks_mirrorcd: received redirection to `http://172.16.0.1/cobbler/ks_mirror/'cd ok, cwd=/cobbler/ks_mirrorlftp 172.16.0.1:/cobbler/ks_mirror/centos-6.4-x86_64> ls-rw-r--r-- 14 2013-03-06 02:28 CentOS_BuildTagdrwxr-xr-x - 2013-07-05 07:42 EFI........drwxr-xr-x - 2013-07-05 07:42 cachedrwxr-xr-x - 2013-07-05 07:42 p_w_picpathsdrwxr-xr-x - 2013-07-05 07:42 isolinuxdrwxr-xr-x - 2013-07-05 07:42 repodatalftp 172.16.0.1:/cobbler/ks_mirror/centos-6.4-x86_64> mirror isolinux/Total: 1 directory, 11 files, 0 symlinks New: 11 files, 0 symlinks37045107 bytes transferred in 3 seconds (10.82M/s)lftp 172.16.0.1:/cobbler/ks_mirror/centos-6.4-x86_64> mirror p_w_picpaths/Total: 2 directories, 7 files, 0 symlinks New: 7 files, 0 symlinks207128660 bytes transferred in 28 seconds (7.18M/s)lftp 172.16.0.1:/cobbler/ks_mirror/centos-6.4-x86_64> bye................................[root@ zly ~]# ls isolinux/boot.cat grub.conf isolinux.bin memtest TRANS.TBL vmlinuzboot.msg initrd.img isolinux.cfg splash.jpg vesamenu.c32[root@ zly ~]# ls p_w_picpaths/pxeboot/initrd.img TRANS.TBL vmlinuz
2、创建挂载光盘镜像的目录并挂载光盘
[root@zly ~]# mkdir /var/ftp/pub/centos-6.4-x86_64 -pvmkdir: created directory `/var/ftp/pub/centos-6.4-x86_64'[root@zly ~]# mount -r /dev/cdrom /var/ftp/pub/centos-6.4-x86_64/[root@zly ~]# cd /var/ftp/pub/centos-6.4-x86_64/[root@zly centos-6.4-x86_64]# lsCentOS_BuildTag isolinux RPM-GPG-KEY-CentOS-Debug-6EFI Packages RPM-GPG-KEY-CentOS-Security-6EULA RELEASE-NOTES-en-US.html RPM-GPG-KEY-CentOS-Testing-6GPL repodata TRANS.TBLp_w_picpaths RPM-GPG-KEY-CentOS-6
三、安装PXE实现部署所依赖的服务
1、安装vsftpd服务,并启动服务；
[root@zly ~]# yum -y install vsftpdLoaded plugins: fastestmirror, refresh-packagekit, securityLoading mirror speeds from cached hostfileSetting up Install ProcessResolving Dependencies--> Running transaction check---> Package vsftpd.x86_64 0:2.2.2-11.el6_3.1 will be installed--> Finished Dependency Resolution.................................Installed: vsftpd.x86_64 0:2.2.2-11.el6_3.1Complete!.................................[root@ zly ~]# service vsftpd startStarting vsftpd for vsftpd: [ OK ][root@ zly ~]# ss -tanlp | grep vsftpdLISTEN 0 32 *:21 *:* users:(("vsftpd",8968,3)) 2、确认已配置好的yum源，并安装dhcp
[root@zly ~]# vim /etc/yum.repos.d/centos.repo[yum1]name=centos6.4baseurl=http://172.16.0.1/cobbler/ks_mirror/centos-6.4-x86_64/enable=1gpgcheck=0[yum2]name=fedorabaseurl=http://172.16.0.1/fedora-epel/6/x86_64/enable=1gpgcheck=0[yum3]name=extrbaseurl=http://172.16.0.1/centos/6/extras/x86_64/enable=1gpgcheck=0........................[root@zly ~]# yum -y install dhcpLoaded plugins: fastestmirror, refresh-packagekit, securityLoading mirror speeds from cached hostfileSetting up Install ProcessResolving Dependencies--> Running transaction check---> Package dhcp.x86_64 12:4.1.1-34.P1.el6.centos will be installed--> Finished Dependency Resolution.................Installed: dhcp.x86_64 12:4.1.1-34.P1.el6.centos Complete!
四、修改dhcp的配置文件
1、dhcp服务是使用PXE的前提，通过dhcp服务可以告知tftp服务的地址，以及要加载的文件；
[root@zly ~]# cp /usr/share/doc/dhcpdhclient-4.1.1/ dhcp-4.1.1/ dhcp-common-4.1.1/[root@zly ~]# cp /usr/share/doc/dhcp-4.1.1/dhcpd.conf.sample /etc/dhcp/dhcpd.confcp: overwrite `/etc/dhcp/dhcpd.conf'? y[root@zly ~]# vim /etc/dhcp/dhcpd.confoption domain-name "xiaozheng.com";option domain-name-servers 172.16.20.8;default-lease-time 43200;max-lease-time 86400;..................subnet 192.168.20.0 netmask 255.255.255.0 { range 192.168.20.1 192.168.20.100 option routers 192.168.20.3}:.,$s@^\([^#]\)@#\1@g 注释当前行及其之后的行[root@ zly ~]# service dhcpd startStarting dhcpd: [ OK ][root@ zly ~]# ss -uanlp | grep dhcpUNCONN 0 0 *:67 *:* users:(("dhcpd",6578,7)) 2、在配置文件中添加指向tftp服务器及PXE文件目录
[root@ zly ~]# vim /etc/dhcp/dhcpd.confsubnet 192.168.20.0 netmask 255.255.255.0{ range 192.168.20.1 192.168.20.100; option routers 192.168.20.3;}next-server 192.168.20.3;filename="pxelinux.0";........[root@ zly ~]# service dhcpd restartShutting down dhcpd: [ OK ]Starting dhcpd: [ OK ] 五、tftp服务的安装配置
1、安装使用tftp服务，查看tftp根目录的‘pxelinux'存放路径，并启动xinetd服务；
[root@ zly ~]# yum -y install syslinux tftp tftp-serverLoaded plugins: fastestmirror, refresh-packagekit, securityLoading mirror speeds from cached hostfileSetting up Install ProcessResolving Dependencies--> Running transaction check---> Package syslinux.x86_64 0:4.02-8.el6 will be installed---> Package tftp.x86_64 0:0.49-7.el6 will be installed---> Package tftp-server.x86_64 0:0.49-7.el6 will be installed........................Installed: syslinux.x86_64 0:4.02-8.el6 tftp.x86_64 0:0.49-7.el6 tftp-server.x86_64 0:0.49-7.el6 Dependency Installed: xinetd.x86_64 2:2.3.14-38.el6 Complete!.........................[root@ zly ~]# cd /etc/xinetd.d/[root@ zly xinetd.d]# lschargen-dgram daytime-stream echo-dgram tcpmux-server time-streamchargen-stream discard-dgram echo-stream tftpdaytime-dgram discard-stream rsync time-dgram[root@ zly xinetd.d]# vim tftp server = /usr/sbin/in.tftpd server_args = -s /var/lib/tftpboot disable = yes..............................[root@ zly xinetd.d]# chkconfig tftp on[root@ zly xinetd.d]# service xinetd restartStopping xinetd: [ OK ]Starting xinetd: [ OK ][root@ zly xinetd.d]# ss -uanlpState Recv-Q Send-Q Local Address:Port Peer Address:PortUNCONN 0 0 *:751 *:* users:(("rpc.statd",1423,5))UNCONN 0 0 *:111 *:* users:(("rpcbind",1404,6))UNCONN 0 0 *:631 *:* users:(("cupsd",1547,9))UNCONN 0 0 *:67 *:* users:(("dhcpd",6664,7))UNCONN 0 0 *:69 *:* users:(("xinetd",6752,5)) 六、配置PXE部署OS所需的安装源
1、从所下载的镜像文件中添加PXE部署OS所需要的相关文件；
[root@ zly ~]# lsanaconda-ks.cfg install.log isolinux pxelinux.0p_w_picpaths install.log.syslog package.xml[root@ zly ~]# cd isolinux/[root@ zly isolinux]# lsboot.cat grub.conf isolinux.bin memtest TRANS.TBL vmlinuzboot.msg initrd.img isolinux.cfg splash.jpg vesamenu.c32......................[root@ zly isolinux]# cp {boot.msg,splash.jpg,vesamenu.c32} /var/lib/tftpboot/[root@ zly isolinux]# cd /var/lib/tftpboot/[root@ zly tftpboot]# lsboot.msg pxelinux.0 splash.jpg vesamenu.c32......................[root@ zly ~]# cp p_w_picpaths/pxeboot/{vmlinuz,initrd.img} /var/lib/tftpboot/[root@ zly ~]# ls /var/lib/tftpboot/boot.msg initrd.img pxelinux.0 splash.jpg vesamenu.c32 vmlinuz 2、创建PXE配置文件
[root@ zly ~]# mkdir /var/lib/tftpboot/pxelinux.cfg[root@ zly ~]# cd /var/lib/tftpboot/pxelinux.cfg/[root@ zly pxelinux.cfg]# ls[root@ zly pxelinux.cfg]# cp /root/isolinux/isolinux.cfg default[root@ zly pxelinux.cfg]# lsdefault[root@ zly pxelinux.cfg]# vim defaultlabel linux menu label ^Install or upgrade an existing system menu default kernel vmlinuz append initrd=initrd.img ks=ftp://192.168.20.3/pub/kickstart/centos6.cfg ...............[root@ zly pxelinux.cfg]# chmod +x default
七、配置PXE所需的kickstart文件
1、创建kickstart文件；
[root@ zly pxelinux.cfg]# mkdir -pv /var/lib/pub/kickstart/mkdir: created directory `/var/lib/pub'mkdir: created directory `/var/lib/pub/kickstart/'[root@ zly pxelinux.cfg]# vim default[root@ zly pxelinux.cfg]# yum -y install system-config-kickstart[root@ zly pxelinux.cfg]# system-config-kickstartXlib: extension "RANDR" missing on display "localhost:11.0"./usr/share/system-config-kickstart/kickstartGui.py:103: GtkWarning: GtkSpinButton: setting an adjustment with non-zero page size is deprecated xml = gtk.glade.XML ("/usr/share/system-config-kickstart/system-config-kickstart.glade", domain="system-config-kickstart")Loaded plugins: fastestmirror, refresh-packagekitLoading mirror speeds from cached hostfile................. *（基图形化界面创建）
需要修改内容如下，其他选项使用默认配置
1）修改安装方法
2）修改磁盘分区
3）修改安装后脚本，并保存
至此kickstart文件创建完毕保存则可以使用
2、修改已经创建的kickstart文件，并重启vsftpd服务
[root@ zly ~]# lsanaconda-ks.cfg p_w_picpaths install.log.syslog package.xmlcentos6.cfg install.log isolinux pxelinux.0[root@ zly ~]# cat anaconda-ks.cfg[root@ zly ~]# vim centos6.cfgurl --url="ftp://192.168.20.3/pub/centos-6.4-x86_64"............clearpart --all --initlabelpart /boot --fstype=ext4 --size=200part pv.008002 --size=61440volgroup vg0 --pesize=8192 pv.008002logvol / --fstype=ext4 --name=root --vgname=vg0 --size=20480logvol swap --name=swap --vgname=vg0 --size=2048logvol /usr --fstype=ext4 --name=usr --vgname=vg0 --size=10240logvol /var --fstype=ext4 --name=var --vgname=vg0 --size=20480...........[root@ zly ~]# service vsftpd restartShutting down vsftpd: [ OK ]Starting vsftpd for vsftpd: [ OK ]
八、使用PXE完成自动化部署OS
新建虚拟机安装OS，将其网卡连接模式改为内网模式vmnet2，启动安装流程，部署过程如下：
1）OS安装选择界面
2）等待NetworkManager配置网卡
3）从属检测
4）安装OS包
5）安装完毕后，重启主机即可使用已安装的系统
至此，基于PXE的自动化部署OS已经基本完成，后续自动化部署敬请关注！