centos 5.4、5.5、5.6的内核都是2.6.18，都可以安装php 5.3。
卸载旧版本apache、php、mysql：
sudo yum erase httpd
sudo yum erase php php-cli
sudo yum erase mysql
下载编译安装apache 2.2.19：
http://httpd.apache.org/download.cgi
cd ~
wget http://mirror.bjtu.edu.cn/apache/httpd/httpd-2.2.19.tar.bz2
tar -jxvf httpd-2.2.19.tar.bz2
cd httpd-2.2.19
sudo yum install gcc
./configure --prefix=/opt/httpd --enable-so --enable-rewrite
make
sudo make install
sudo /opt/httpd/bin/httpd -k start
安装完apache，用浏览器访问http://localhost，能正常显示说明装好了。
下载安装mysql 5.5.13：
http://dev.mysql.com/downloads/mysql/#downloads
下载这2个（64位的）： MySQL-client MySQL-server
sudo yum install libaio
sudo rpm -i MySQL-client-5.5.13-1.rhel5.x86_64.rpm
sudo rpm -i MySQL-server-5.5.13-1.rhel5.x86_64.rpm
sudo /etc/init.d/mysql start
/usr/bin/mysqladmin -u root password '1'
sudo cp /usr/share/mysql/my-medium.cnf /etc/my.cnf
sudo /etc/init.d/mysql restart
mysql -uroot -p1
下载编译安装php 5.3.6：
http://php.net/downloads.php
sudo yum install libxml2 libxml2-devel curl curl-devel libjpeg libjpeg-devel libpng libpng-devel libmcrypt libmcrypt-devel libtool-ltdl-devel
tar -jxvf php-5.3.6.tar.bz2
cd php-5.3.6
./configure --prefix=/opt/php -with-apxs2=/opt/httpd/bin/apxs --with-curl --with-mcrypt --enable-mbstring --with-iconv --with-gd -with-jpeg-dir=/usr/local/lib --enable-pdo --with-pdo-mysql=mysqlnd --with-mysqli=mysqlnd --with-mysql=mysqlnd
make
sudo make install
sudo cp php.ini-development /opt/php/lib/php.ini
sudo ln -s /opt/php/bin/php /usr/bin/php
sudo vi /opt/php/lib/php.ini
把include_path前面的分号删除，改成include_path = "/opt/php/lib/php"
sudo vi /opt/httpd/conf/httpd.conf
在最下面加入一行AddHandler application/x-httpd-php .php
sudo /opt/httpd/bin/httpd -k restart
sudo vi /opt/httpd/htdocs/phpinfo.php
phpinfo.php的内容如下：
<?php
phpinfo();
?>
安装完php，重启apache，用浏览器访问http://localhost/phpinfo.php，能正常显示说明php装好了。搜索mysqlnd、pdo_mysql、mysqli，如果有，则说明php能访问mysql。
把apache加入系统service，开机自启动
sudo cp /opt/httpd/bin/apachectl /etc/init.d/httpd
sudo vi /etc/init.d/httpd
在文件开头加入下面几行：
#!/bin/sh
# chkconfig: 2345 85 15
# description: Apache is a World Wide Web server.
sudo chmod +x /etc/init.d/httpd
sudo /sbin/chkconfig --add httpd
sudo /sbin/chkconfig --list httpd
sudo ln -s /sbin/chkconfig /usr/bin/chkconfig
sudo ln -s /sbin/service /usr/bin/service
把mysql加入系统service，开机自启动
sudo /sbin/chkconfig --list mysql
通过rpm安装的mysql，已经开机自启动了。
安装php扩展ssh2
先安装libssh2
http://sourceforge.net/projects/libssh2/
./configure
make
sudo make install
再安装ssh2
http://pecl.php.net/package/ssh2
/opt/php/bin/phpize && ./configure --with-ssh2 && make
sudo make install
在/opt/php/lib/php.ini中加1行：
extension=ssh2.so
centos 5.4升级到5.6：
先修改更新源为国内的更新源
cd /etc/yum.repos.d
sudo mv CentOS-Base.repo CentOS-Base.repo.save
sudo wget http://centos.ustc.edu.cn/CentOS-Base.repo
清理残留文件然后更新标准库，再升级
sudo yum clean all
sudo yum update glibc*
sudo yum update yum* rpm* python*
sudo yum clean all
sudo yum update
sudo reboot