How to Install Apache on CentOS 7

This guide explains how to install and configure the Apache web server on CentOS 7. Apache is an open-source web server that can be configured to serve a single or multiple websites using the same Linode.

Before you begin

1. Ensure you have followed both the Getting Started and Securing Your Server guides.

2. Check that the Linode’s hostname is set. To check the hostname run:

   hostname
   hostname -f
   

   The first command displays a short hostname, and the second displays the Fully Qualified Domain Name (FQDN).

3. Use yum to update the system and make sure everything is up to date:

   sudo yum update
   

Configure firewalld to allow web traffic

By default, CentOS 7 is set to block web traffic. Run the following commands to allow web traffic through the firewall:

sudo firewall-cmd --add-service=http --permanent && sudo firewall-cmd --add-service=https --permanent
sudo systemctl restart firewalld

Install and configure Apache

Installing Apache

1. Install Apache 2.4 using yum:

   sudo yum install httpd
   

2. After you confirm the installation, let yum install Apache and its dependencies.

Configuring httpd.conf

1. Before changing any configuration files, Linode recommends that you make a backup. To make a backup of the httpd.conf file, use:

   cp /etc/httpd/conf/httpd.conf ~/httpd.conf.backup

2. Update the httpd.conf file with the document root directory in order to point Apache to the files of the website and also add the <IfModule prefork.c> section to adjust the resource use settings (these are a good starting point for a Linode 2GB)

   File: /etc/httpd/conf/httpd.conf

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   DocumentRoot "/var/www/html/example.com/public_html" ... <IfModule prefork.c> StartServers 5 MinSpareServers 20 MaxSpareServers 40 MaxRequestWorkers 256 MaxConnectionsPerChild 5500 </IfModule>

Configuring a name-based virtual host

A single domain

There are multiple ways to set up a virtual host, but this section explains and recommends one of the easier methods.

1. Within the conf.d directory, create the file vhost.conf to store the virtual host configurations.

2. Edit vhost.conf using the following example. Remember to substitute the domain name for example.com.

   File: /etc/httpd/conf.d/vhost.conf

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   NameVirtualHost *:80 <VirtualHost *:80> ServerAdmin webmaster@example.com ServerName example.com ServerAlias www.example.com DocumentRoot /var/www/html/example.com/public_html/ ErrorLog /var/www/html/example.com/logs/error.log CustomLog /var/www/html/example.com/logs/access.log combined </VirtualHost>

3. Create the directories referenced in the previous step:

   sudo mkdir -p /var/www/html/example.com/{public_html,logs}
   

   Note

   The ErrorLog and CustomLog entries are suggested for more specific logging, but are not required. If they are defined as in the previous step, create the logs directories before you restart Apache.

4. Enable Apache to start at boot, and restart the service for the above changes to take effect:

   sudo systemctl enable httpd.service
   sudo systemctl restart httpd.service
   

5. Visit your domain to test the Apache server. A default Apache page will be visible if no index page is found in the document root declared in httpd.conf:

Multiple Domains

Additional domains may be used with the vhost.conf file as necessary. When new requests come in from the internet, Apache checks which VirtualHost block matches the requested URL and serves the appropriate content:

To add additional domains, copy the example in the previous section and add it to the end of the existing file, modify the values for the new domain, create the directories, restart Apache, and test the newly added domain. Repeat as necessary.

Congratulations! You’ve set up Apache and you’re now ready to host websites. If you’re wondering what additional configuration changes are available to get the most out of the server, here are some optional steps.

Next Steps: Additional security and high availability

Secure the server with SELinux

SELinux is a mandatory access control (MAC) system that confines privileged processes and automates security policy creation. To enable it on your Linode, see the Beginner’s Guide to SELinux on CentOS 7.

Secure the site with SSL

To add additional security to the site, consider enabling a secure sockets layer (SSL) certificate.

Install and Configure GlusterFS, Galera, and XtraDB for High Availability

Consult the Host a Website with High Availability guide to mitigate downtime through redundancy, monitoring, and failover.

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• CentOS Linux Home Page
• Apache HTTP Server Documentation