Overview

This document describes the system requirements for your cPanel & WHM installation in a CentOS server. You can install cPanel & WHM on CentOS version 7 and Red Hat® Enterprise Linux® (RHEL) version 7.

Before you install cPanel & WHM or cPanel DNSOnly®, make certain that your CentOS or RHEL system meets all of our minimum requirements for new installations.

License

Each cPanel & WHM server requires its own license. If you do not already own a license for cPanel & WHM, you can obtain one for your server’s IP address. To obtain a cPanel & WHM license, visit the cPanel Store.

Networking requirements

Hostname

Your hostname must meet the following requirements:

• Be a registered and fully-qualified domain name.
• Does not match any of your server’s domains.
• Be a maximum of 60 characters in length.
• Resolves to a valid IPv4 or IPv6 address.

IP addresses

Your IP address must meet the following requirements:

• Be a valid IP address.
• Be a 1:1 NAT and NAT loopback configuration if your server resides on a NAT-configured network.

Ethernet device

You must configure your Ethernet device with a static IP address and fully-qualified hostname. The system attempts to detect and set the Ethernet device during the installation process.

Firewalls

The installer will attempt to open the necessary ports during the installation process. We recommend that you disable OS firewalls before you run the cPanel & WHM installation. When the installation process finishes, we recommend that you then configure a firewall with a third-party client such as APF or CSF.

To deactivate firewalls on CentOS 7 and RHEL 7, run the following commands to deactivate the firewall, where ~/firewall.rules represents the firewall rules file:

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iptables-save > ~/firewall.rules
systemctl stop firewalld.service
systemctl disable firewalld.service

Utilities

For systems that run CentOS 7 and RHEL 7: you must disable Network Manager before you run the cPanel & WHM installation. The Network Manager service automates the network’s settings and disrupts connections to the IP addresses that reside in the ipaliases module.

Hardware requirements

Hardware considerations

When you choose a server, consider the following questions:

How many sites do you plan to host?

Servers that host a large number of websites with associated email addresses and databases require more processing power, disk space, and RAM.

What kind of web hosting do you plan to do?

You can run cPanel & WHM with the minimum requirements in the table above. However, servers that host videos, music, or high-volume applications require more processing power, disk space, and RAM.

If you plan to host CPU-intensive applications on a virtual machine, we recommend that you evaluate your CPU load usage. You may need to assign additional CPU cores to satisfy the processing requirements of high-performance applications.

CentOS and RHEL versions

cPanel, L.L.C. supports all of the official production release kernels for CentOS 7 and Red Hat Enterprise Linux 7.

CentOS

You can install cPanel & WHM on CentOS version 7.

To install CentOS, read the CentOS Installation Guide.

Red Hat Enterprise Linux

You can install cPanel & WHM in Red Hat Enterprise Linux version 7.

To install Red Hat Enterprise Linux on a clean server, read the Red Hat Installation Guide.

After you install Red Hat Enterprise Linux, you must run the rhn_register command to register the server with the Red Hat Network.

If your server is on the Red Hat Network and uses the satellite subscription method, you must install the subscription-manager package before you install cPanel & WHM.

To subscribe to the Optional RPMs channel for RHEL 7, run the following command:

subscription-manager repos --enable rhel-7-server-optional-rpms

You may need to subscribe to additional channels to maintain all of the packages that cPanel & WHM requires.

Operating state

In Linux, the operating system possesses several levels of operating states. Each different level represents a system configuration and allows users to access different processes.

Change the operating state

To change the runlevel for CentOS or RHEL, run the following command as the root user, where TARGET.target represents the operating state target:

systemctl set-default TARGET.target

For a complete list of targets, visit freedesktop.org’s systemd.target article.

Disable SELinux

You must disable SELinux to make your system compatible with cPanel & WHM.

To disable SELinux security features, use one of the following methods:

• Use the graphical interface to disable SELinux while you configure your operating system, and then reboot the server.

• Edit the /etc/selinux/config file to set the SELINUX parameter to disabled, and then reboot the server. The contents of the /etc/selinux/config file should resemble the following example:

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  # This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. SELINUX=disabled # SELINUXTYPE= can take one of these two values: # targeted - Only targeted network daemons are protected. # strict - Full SELinux protection. SELINUXTYPE=targeted

  Important:

  Make certain that the number sign (#) does not precede SELINUX=disabled. If a # precedes this configuration option, the system ignores the option.

Perl installation

Perl must exist on your server before the installation script for cPanel & WHM can run successfully. If Perl does not exist during installation, the cPanel & WHM installer attempts to install Perl via the yum -y install perl command.

• If you see errors during this step of the installation process, read our Troubleshoot Your Installation documentation.

• For more information about Perl on your server, and which versions of Perl ship with specific operating systems, read our Guide to Perl in cPanel & WHM documentation. cPanel & WHM servers use multiple Perl environments.

Filesystems

When you install your operating system (OS), we recommend that you use the XFS® or ext4 filesystems.

Partitions

Inodes

In Linux, an inode is a filesystem object that contains the owner, permissions, and other important metadata. Every file, image, directory, email, and symbolic link on your server requires an inode.

• On average, files on webservers are usually smaller than on other types of servers. Therefore, we recommend that you allocate more than the default number of inodes on your server’s partitions.

• If you install everything on a single partition, the base cPanel & WHM or cPanel DNSOnly installation requires at least 1,000,000 inodes, plus at least 50,000 inodes per cPanel account that you plan to host.

Virtual environments

cPanel products support the following virtual environments with the following restrictions:

• KVM — No additional restrictions.

  Note:

  If you use a Linux bridge on a KVM server, you may experience problems with multicast routing.

  • These problems affect the server’s ability to resolve nodes on the network. For example, IPv6 Stateless Address Autoconfiguration (SLAAC) addresses may drop off intermittently, or the server may experience problems when it attempts to find the router.

  • To resolve this issue, set the multicast_router system knob value to 2. For more information, read this CentOS-virt mailing list thread.

• Linux Containers — cPanel & WHM requires additional configuration to run inside a Linux Container. For more information, read our Linux Containers documentation.

• Linux-VServer — No additional restrictions.

• Microsoft Server® 2008 Hyper-V, Microsoft Server 2012 Hyper-V — cPanel only supports the drivers and configurations that Microsoft® provides.

• OpenVZ

  • cPanel only supports stable releases.

• Oracle VM VirtualBox, VirtualBox OSE — No additional restrictions.

• QEMU — No additional restrictions.

• SmartOS — cPanel & WHM detects this virtual environment and reports as functional, but we do not officially support it.

• Virtuozzo™

  • We support Virtuozzo version 7 and earlier.
  • We only support Virtuozzo KVM and container environments.

• VMware ESXi™ Server — No additional restrictions.

• Xen, XenEnterprise™, XenExpress™, XenServer™ — No additional restrictions.

Compatible browsers

We specifically test cPanel & WHM with certain browsers to ensure compatibility. Other browsers will likely function, but may appear differently or experience issues with certain features.

We develop and test cPanel & WHM to function with the latest versions of the following browsers:

• Chrome™ (MacOS®, Microsoft® Windows®, Linux)

• Firefox (MacOS, Windows, Linux)

• Microsoft Edge (Windows)

• Safari® (MacOS)

Mobile versions of Firefox, Chrome, and Safari are also compatible with cPanel & WHM.