方法一、简单安装（通过yum）
安装epel-release
rpm -ivh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm安装PHP7的rpm源
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm安装PHP7
yum install php70w
方法二、编译安装
下载php7
wget -O php7.tar.gz http://cn2.php.net/get/php-7.1.1.tar.gz/from/this/mirror解压php7
tar -xvf php7.tar.gz
进入php目录
cd php-7.0.4
安装依赖包
# 直接复制下面一行（不包括本行）
yum install libxml2 libxml2-devel openssl openssl-devel bzip2 bzip2-devel libcurl libcurl-devel libjpeg libjpeg-devel libpng libpng-devel freetype freetype-devel gmp gmp-devel libmcrypt libmcrypt-devel readline readline-devel libxslt libxslt-devel编译配置（如果出现错误，基本都是上一步的依赖文件没有安装所致）
嫌麻烦的可以从这一步起参考PHP官方安装说明： http://php.net/manual/zh/install.unix.nginx.php
./configure \
--prefix=/usr/local/php \
--with-config-file-path=/etc \
--enable-fpm \
--with-fpm-user=nginx \
--with-fpm-group=nginx \
--enable-inline-optimization \
--disable-debug \
--disable-rpath \
--enable-shared \
--enable-soap \
--with-libxml-dir \
--with-xmlrpc \
--with-openssl \
--with-mcrypt \
--with-mhash \
--with-pcre-regex \
--with-sqlite3 \
--with-zlib \
--enable-bcmath \
--with-iconv \
--with-bz2 \
--enable-calendar \
--with-curl \
--with-cdb \
--enable-dom \
--enable-exif \
--enable-fileinfo \
--enable-filter \
--with-pcre-dir \
--enable-ftp \
--with-gd \
--with-openssl-dir \
--with-jpeg-dir \
--with-png-dir \
--with-zlib-dir \
--with-freetype-dir \
--enable-gd-native-ttf \
--enable-gd-jis-conv \
--with-gettext \
--with-gmp \
--with-mhash \
--enable-json \
--enable-mbstring \
--enable-mbregex \
--enable-mbregex-backtrack \
--with-libmbfl \
--with-onig \
--enable-pdo \
--with-mysqli=mysqlnd \
--with-pdo-mysql=mysqlnd \
--with-zlib-dir \
--with-pdo-sqlite \
--with-readline \
--enable-session \
--enable-shmop \
--enable-simplexml \
--enable-sockets \
--enable-sysvmsg \
--enable-sysvsem \
--enable-sysvshm \
--enable-wddx \
--with-libxml-dir \
--with-xsl \
--enable-zip \
--enable-mysqlnd-compression-support \
--with-pear \
--enable-opcache正式安装
make && make install
配置环境变量
vi /etc/profile
在末尾追加
PATH=$PATH:/usr/local/php/bin
export PATH执行命令使得改动立即生效
source /etc/profile
配置php-fpm
cp php.ini-production /etc/php.ini
cp /usr/local/php/etc/php-fpm.conf.default /usr/local/php/etc/php-fpm.conf
cp /usr/local/php/etc/php-fpm.d/www.conf.default /usr/local/php/etc/php-fpm.d/www.conf
cp sapi/fpm/init.d.php-fpm /etc/init.d/php-fpm
chmod +x /etc/init.d/php-fpm启动php-fpm
/etc/init.d/php-fpm start
