How to install and configure Apache on CentOS or Red Hat

Red Hat is a very popular choice of Linux distribution for server deployment and Apache is one of the most popular web server software. Red Hat and Apache is then one of the more popular combination for web server deployment while CentOS is being used as a free replacement fr Red Hat.

Apache is fully supported by both Red Hat and CentOS and can easily be installed from the command line using yum.

Steps to install and configure Apache on CentOS or Red Hat:

Launch terminal application.

Install httpd package using yum.

$ sudo yum install --assumeyes httpd
[sudo] password for user:
Last metadata expiration check: 0:04:30 ago on Mon 17 Feb 2020 05:37:42 PM EST.
Dependencies resolved.
=====================================================================================================
 Package                 Arch        Version                                    Repository      Size
=====================================================================================================
Installing:
 httpd                   x86_64      2.4.37-16.module_el8.1.0+256+ae790463      AppStream      1.7 M
Installing dependencies:
 apr                     x86_64      1.6.3-9.el8                                AppStream      125 k
 apr-util                x86_64      1.6.1-6.el8                                AppStream      105 k
 centos-logos-httpd      noarch      80.5-2.el8                                 AppStream       24 k
 httpd-filesystem        noarch      2.4.37-16.module_el8.1.0+256+ae790463      AppStream       35 k
 httpd-tools             x86_64      2.4.37-16.module_el8.1.0+256+ae790463      AppStream      103 k
 mod_http2               x86_64      1.11.3-3.module_el8.1.0+213+acce2796       AppStream      158 k
Installing weak dependencies:
 apr-util-bdb            x86_64      1.6.1-6.el8                                AppStream       25 k
 apr-util-openssl        x86_64      1.6.1-6.el8                                AppStream       27 k
Enabling module streams:
 httpd                               2.4

Transaction Summary
=====================================================================================================
Install  9 Packages

Total download size: 2.3 M
Installed size: 6.6 M

Configure Apache options as necessary.
```
$ sudo vi /etc/httpd/conf/httpd.conf
```
Apache web server configuration files

Guide listing for Apache

Test Apache configuration for errors.

$ sudo apachectl configtest
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::e5f:4565:1b9c:6e87. Set the 'ServerName' directive globally to suppress this message
Syntax OK

How to test Apache configuration without restarting service

Restart httpd service once Apache configuration contains no error.
```
$ sudo systemctl restart httpd
```

Configure httpd service to automatically start during system boot.

$ sudo systemctl enable httpd
Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service → /usr/lib/systemd/system/httpd.service.

Add http and/or https services to the firewall.

$ sudo firewall-cmd --permanent --add-service=http --add-service=https
success

Reload firewall for the added rules to be enabled.
```
$ sudo firewall-cmd --reload
success
```

Access the website using browser or command line tools to test if your Apache web server is up and running.

$ curl 127.0.0.1
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE HTML>
<html lang="en">
  <head>
    <title>CentOS 提供的 Apache HTTP 服务器测试页</title>
    <meta charset="utf-8"/>
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"/>
    <link rel="shortcut icon" href="http://www.centos.org/favicon.ico"/>
    <link rel="stylesheet" media="all" href="noindex/common/css/bootstrap.min.css"/>
    <link rel="stylesheet" media="all" href="noindex/common/css/styles.css"/>
  </head>
##### snipped