Installation Guide - System Requirements for Ubuntu


This document describes the system requirements for your cPanel & WHM installation on an Ubuntu® server. Starting in cPanel & WHM version 102, you can install cPanel & WHM on Ubuntu version 20.04 LTS.

Before you install cPanel & WHM, make certain that your Ubuntu system meets all of our minimum requirements for new installations.

  • This document lists the minimum requirements to install cPanel & WHM. An Ubuntu server that meets only these requirements may not function properly, especially when under a heavy load.

  • You must log in to the server as the root user in order to install cPanel & WHM. If you do not possess root-level access, contact your system administrator or hosting provider for assistance.


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.

  • You cannot transfer a single cPanel & WHM license across multiple servers. This action may cause cPanel, L.L.C. to lock your license. For more information, read our Legal Agreements documentation.

  • Due to networking requirements, you cannot run an IPv6-only cPanel & WHM server. You must have at least one IPv4 address.

  • cPanel & WHM requires a valid license. If this is a new installation, you can activate a free 15-day trial license.

  • In order to activate a new license, you must have a cPanel Store account with a verified email address.

  • cPanel DNSOnly requires a DNSOnly license, which the server automatically obtains during installation.

Networking requirements


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.
  • Resolve to a valid IPv4 or IPv6 address.
If your server does not use a resolvable fully-qualified domain name as the hostname, it will automatically receive one from cPanel, L.L.C. For more information, read our Automatically-Issued Hostnames documentation.

IP addresses

Your system must meet the following requirements:

  • Have a valid IP address.
  • Have 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 will detect and set up the Ethernet device during installation.


You cannot use an IP address that a DHCP service dynamically assigns to your server.


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.


Ubuntu distributions allow you to disable the firewall for the operating system’s installation configuration. We strongly recommend that you use this method.

To deactivate firewalls on Ubuntu, run the following commands, where ~/firewall.rules represents the firewall rules file:

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

Hardware requirements

Operating system and version Processor RAM Disk Space Architecture
Ubuntu 20.04 LTS
  • Minimum: 1.1 GHz
  • Recommended: 2 GHz
  • Minimum: 1 GB
  • Recommended: 4 GB
  • Minimum: 20 GB
  • Recommended: 40 GB

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.

  • The cPanel & WHM installation and upgrade processes require at least 5 GB of additional disk space in the /usr/local/cpanel directory.

  • Before the installation process begins, the system checks to ensure that your server meets these minimum memory requirements. If your server does not meet these requirements, the installation process will return an error message and then exit.

Ubuntu versions

You can install cPanel & WHM on Ubuntu 20.04 LTS (Focal Fossa).

  • We recommend that you use the minimal installer.

  • Do not install SELinux on your server. SELinux is not compatible with cPanel & WHM.

To install Ubuntu, read the Installing Ubuntu 20.04 documentation.

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.

Operating system Operating state Setting Location
Ubuntu Target /usr/lib/systemd/system

Change the operating state

To change the OS runlevel for Ubuntu, run the following command as the root user, where represents the operating state target:

systemctl set-default

For a complete list of targets, visit Ask Ubuntu’s How do I change the runlevel on systemd? article.

SELinux and AppArmor

Do not install SELinux on your server. SELinux is not compatible with cPanel & WHM.

Ubuntu installations run AppArmor by default. AppArmor is compatible with cPanel & WHM. You do not need to disable AppArmor to install cPanel & WHM.

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 apt -y install perl perl-base 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.


We strongly recommend that you allow your operating system’s distribution to control the system Perl installation. Do not customize this Perl installation.


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


We only develop and test cPanel & WHM on filesystems that support flock. Some network filesystems (for example, NFS) may require additional configuration in order to function properly. However, these configurations are difficult to implement successfully and we do not support them.


  • Your system’s applications may require additional swap space. Consult your application’s software developers or documentation for their swap space recommendations.

  • Additional partitions improve performance for some servers, especially servers with high email volume. The OS can only access a limited number of files per partition.

Partition RAM and minimum size
/ N/A — Grow to fill disk (40 GB recommended, 20 GB minimum).
To host a greater number of accounts, allocate more disk space to this partition.
  • 2 GB or less — Two times the amount of RAM on the server.
  • 2 GB to 4 GB — The same as the amount of RAM on the server.
  • 4 GB or more — 4 GB


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.


    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 the 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® Server, VMware ESX 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.


These browsers support some email features. The interfaces in cPanel & WHM will likely function, but you may notice minor defects or inconveniences that relate to specific functionality.


We only support the MySQL® 8.0 database server on Ubuntu 20.04 LTS. You cannot use any other database service or version.


The cPanel installer automatically installs MySQL 8.0 during the installation process.


We only support the PowerDNS nameserver on Ubuntu 20.04 LTS. You cannot use any other nameserver.


The cPanel installer automatically installs PowerDNS during the installation process.