在阿里云主机上，操作系统是Centos6，php版本是5.3。因为安装Yii2.0的需要，我要升级php为5.4。因为还有5.5和5.6，当然要升到高版本了。我决定升到5.6。
首先，按照这里的步骤
只有php-fpm没有正确安装，所以无法启动之。下面试图单独安装。
[root@AY14022011465274454aZ ~]# yum install php-fpm
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.tuna.tsinghua.edu.cn
* updates: mirrors.aliyun.com
* webtatic: uk.repo.webtatic.com
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package php-fpm.x86_64 0:5.3.3-48.el6_8 will be installed
--> Processing Dependency: php-common(x86-64) = 5.3.3-48.el6_8 for package: php-fpm-5.3.3-48.el6_8.x86_64
--> Running transaction check
---> Package php-common.x86_64 0:5.3.3-48.el6_8 will be installed
--> Processing Conflict: php56w-common-5.6.26-1.w6.x86_64 conflicts php-common < 5.6
--> Finished Dependency Resolution
Error: php56w-common conflicts with php-common
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest
# yum install php56w-fpm
# service php-fpm start
Starting php-fpm: Failed loading /usr/lib64/php/modules/ZendGuardLoader.so: /usr/lib64/php/modules/ZendGuardLoader.so: undefined symbol: zend_get_hash_value
[ OK ]
（这个错误信息是怎么回事？此后一直伴随，好在没有其它影响，先不管它）
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后续：
1、执行数据库操作时，找不到PDO模块
试着用下面指令
# yum install -y libxml2-devel openssl-devel libcurl-devel libjpeg-devel libpng-devel libicu-devel openldap-devel freetype freetype-devel # --没用
# yum install php56w.x86_64 php56w-cli.x86_64 php56w-common.x86_64 php56w-gd.x86_64 php56w-ldap.x86_64 php56w-mbstring.x86_64 php56w-mcrypt.x86_64 php56w-mysql.x86_64 php56w-pdo.x86_64 #--出错
# yum install php56w-pdo #--成功
重启php-fpm服务，这次yii出现新的错误
CDbConnection failed to open the DB connection: could not find driver
# yum install php56w-mysql
重启服务，这次yii不出错了，但渲染一小块内容，确切地说，只渲染action自己的view的那一块东西，layout/main.php的没过来。
# yum install php56w-mbstring
这次渲染正确了。
发现在饭店查询时出现错误：
include(DOMDocument.php): failed to open stream: No such file or directory
# yum install php56w-dom
成功了。（估计是在解析xml的时候出错了。）
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以上是为记录。留作备忘。