一、virbr0虚拟网卡的卸载方法
在使用双机软件过程中，如果系统是centos 5.x 默认系统安装完成后为xen内核，那么xen内核引导启动后就会有虚拟网卡（vethx、vif0.x、virbr0、xenbr1等）存在。
这就会直接导致双机软件的两台机器中都会有相同的IP地址存在（virbr0网卡的IP地址都为192.168.122.1）。所以会导致双机系统中的主机关机时，备机不会接管的现象。所以，需要将virbr0卸载掉：
执行命令：yum remove -y libvirt*，用ifconfig -a查看网卡virbr0是否卸载。
如果执行yum报错， 可以vi /etc/yum/plugincon.d/rhnplugin.conf然后将文件中的enable=1改成enable=0，目的是先禁用此功能，再执行yum remove libvirt进行卸载。
重启系统
二、卸载network manager
yum remove NetworkManager –y
设置关闭图形化界面（安装图形化界面，是为了可以应用eclipse，一般应用服务器不会选择安装图形化）
systemctl set-default multi-user.target
三、关闭不必要的服务
chkconfig nfs offchkconfig pcmcia offchkconfig lpd offchkconfig autofs offchkconfig anacron offchkconfig portmap offchkconfig isdn offchkconfig nfslock offchkconfig sendmail offchkconfig cups offchkconfig smartd offchkconfig bluetooth offchkconfig netfs offchkconfig rpcgssd offchkconfig rpcidmapd offchkconfig rpcbind offchkconfig pcscd offchkconfig smolt offchkconfig cups offchkconfig isdn offchkconfig ip6tables offsystemctl disable nfssystemctl disable pcmciasystemctl disable lpdsystemctl disable autofssystemctl disable anacronsystemctl disable portmapsystemctl disable isdnsystemctl disable nfslocksystemctl disable sendmailsystemctl disable cupssystemctl disable smartdsystemctl disable bluetoothsystemctl disable netfssystemctl disable rpcgssdsystemctl disable rpcidmapdsystemctl disable rpcbindsystemctl disable pcscdsystemctl disable smoltsystemctl disable cupssystemctl disable isdnsystemctl disable ip6tablessystemctl disable firewalld四、常用包安装
yum -y install gccyum -y install gcc-c++yum -y install net-snmpyum -y install ntpyum -y install unzipyum -y install vim-enhancedyum -y install wgetyum -y install telnetyum -y install kernel-develyum -y install fingeryum -y install sshyum -y install nslookupyum -y install zlib-develyum -y install krb5-develyum -y install sysstatyum -y install lsofyum -y install fuseryum -y install bind-utilsyum -y install glancesyum -y install dstatyum -y install net-toolsyum -y install vimyum -y install wget
