1. Install php

Current system environment

[root@localhost ~]# cat /etc/redhat-release 
CentOS Linux release 7.5.1804 (Core) 
[root@localhost ~]# uname -sr
Linux 4.16.11-1.el7.elrepo.x86_64

Install yum source

php 7 has two yum sources to choose from, one is webmatic and the other is remi.

Add webmatic source (not accessible, not used)

# rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm

Add remi source
Because I can't access the webmatic source here, I use the remi source

rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
rpm -Uvh http://rpms.remirepo.net/enterprise/remi-release-7.rpm
yum clean all && yum makecache

View installable versions of php

[root@localhost ~]# yum list | grep php7 | more
 * remi-php73: mirror.innosol.asia
mod_php72u.x86_64                         7.2.8-1.ius.centos7          @ius     
php72u-common.x86_64                      7.2.8-1.ius.centos7          @ius     
php73.x86_64                              1.0-0.1.el7.remi             @remi-safe
php73-php-cli.x86_64                      7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-common.x86_64                   7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-fpm.x86_64                      7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-gd.x86_64                       7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-json.x86_64                     7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-ldap.x86_64                     7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-mbstring.x86_64                 7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-mysqlnd.x86_64                  7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-opcache.x86_64                  7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-pdo.x86_64                      7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-pecl-mysql.x86_64               1.0.0-0.19.20180226.647c933.el7.remi
php73-php-snmp.x86_64                     7.3.0~alpha4-1.el7.remi      @remi-safe
php73-php-xml.x86_64                      7.3.0~alpha4-1.el7.remi      @remi-safe
php73-runtime.x86_64                      1.0-0.1.el7.remi             @remi-safe
mod_php70u.x86_64                         7.0.31-1.ius.centos7         ius      
mod_php71u.x86_64                         7.1.20-1.ius.centos7         ius      
...........................

Select the corresponding version to install. Install php7.3 here

# yum install –y php73

To view the file directory:

[root@localhost ~]# find / -name php
/var/opt/remi/php73/lib/php
/opt/remi/php73/root/usr/bin/php
/opt/remi/php73/root/usr/lib64/php
/opt/remi/php73/root/usr/share/php

Import environment variables

[root@localhost ~]# vim /etc/profile
PATH=$PATH:/opt/remi/php73/root/usr/bin
export PATH
[root@localhost ~]# source /etc/profile

View php version

[root@localhost ~]# php -v
PHP 7.3.0alpha4 (cli) (built: Jul 17 2018 14:06:14) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.0-dev, Copyright (c) 1998-2018 Zend Technologies

2. Install php extension

yum install –y php73-php-mysql php73-php-snmp php73-php-xml php73-php-ldap php73-php-gd php73-php-mbstring php73-php-fpm

3. Install the mod_php module

This module supports running PHP as an Apache module. mod_php73 is not found here. Install mod_php72u directly
View version

[root@localhost ~]# yum list | grep mod_php
mod_php72u.x86_64                         7.2.8-1.ius.centos7          @ius     
mod_php70u.x86_64                         7.0.31-1.ius.centos7         ius      
mod_php71u.x86_64                         7.1.20-1.ius.centos7         ius  

Execution and installation

[root@localhost ~]# yum install -y mod_php72u
Installed:
  mod_php72u.x86_64 0:7.2.8-1.ius.centos7 

Check the directory / etc/httpd/modules / for two more files (omitted here for httpd installation, just install by yourself)

[root@localhost ~]# ll /etc/httpd/modules/
total 13288
-rwxr-xr-x 1 root root 5124368 Jul 20 01:06 libphp7.so
-rwxr-xr-x 1 root root 5313928 Jul 20 01:06 libphp7-zts.so

Configure the httpd.conf file, load the libphp7.so module, and add the following at the end of the file

[root@localhost ~]# vim /etc/httpd/conf/httpd.conf
....
LoadModule php7_module        /usr/lib64/httpd/modules/libphp7.so

Create a php page and test the php environment,

[root@localhost ~]# vim /var/www/html/index.php 
<?php
    phpinfo();
?>

Restart httpd service and test

# systemctl restart httpd 

Access server address http://192.168.92.56

Why is it 7.2.8, not 7.3? This is just an experimental environment test, please do not use it in the production environment easily!