查看系统版本
lsb_release -a
更新之前查看当前PHP版本避免重复更新
# php -v
检查当前PHP的安装包
# yum list installed | grep php
完全移除当前PHP安装包以免起冲突
# yum remove php*
默认的yum源无法升级PHP，需要添加第三方yum源，我们选择webtatic库
CentOs 5.x
rpm -Uvh http://mirror.webtatic.com/yum/el5/latest.rpm
CentOs 6.x
rpm -Uvh http://mirror.webtatic.com/yum/el6/latest.rpm
CentOs 7.X
rpm -Uvh https://mirror.webtatic.com/yum/el7/epel-release.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
我们以php7.1为例
1.查看yum源是否有php7.1安装包
yum list php71
2.安装php及相关插件
安装php7.0
yum install -y php70w.x86_64 php70w-cli.x86_64 php70w-common.x86_64 php70w-gd.x86_64 php70w-ldap.x86_64 php70w-mbstring.x86_64 php70w-mcrypt.x86_64 php70w-mysql.x86_64 php70w-pdo.x86_64 php70w-fpm
其他版本php安装
如果想安装php5.5或者5.6版本，将上面的php70w替换为php55w或者php56w就可以了。
安装php7.1
yum install -y php71w-fpm php71w-opcache php71w-cli php71w-gd php71w-imap php71w-mysqlnd php71w-mbstring php71w-mcrypt php71w-pdo php71w-pecl-apcu php71w-pecl-mongodb php71w-pecl-redis php71w-pgsql php71w-xml php71w-xmlrpc php71w-devel mod_php71w
3.查看当前php版本
php -v