What are the alternatives to Citrix Hypervisor?

The Citrix hypervisor is known for its stability and high performance. But in some situations, some alternatives may prove to be a better choice. Find out in our article when to opt for an alternative to this virtualization solution.

What is Citrix Hypervisor?

Citrix Hypervisor is a virtualization platform from Citrix Systems. The hypervisor began as an open source project called Xen in 2003, started at the University of Cambridge. It is a virtualization solution bare metal which is installed directly on the physical hardware of a server in order to run multiple virtual machines (VMs for Virtual Machine) on the same server. To do this, the hypervisor manages hardware resources such as CPU, RAM, and storage space to ensure optimal distribution between the different VMs.

The Citrix hypervisor supports a wide range of operating systems, including Windows and various Linux distributions. You can use Citrix to create automated backups and migrate live VMs. Management tools such as XenCenter are also available for monitoring and controlling VMs and resources.

Best Alternatives to Citrix

Some virtualization solutions offer specific features or technologies that are better suited for certain use cases. Below we present three alternatives to Citrix Hypervisor.

KVM

KVM (Kernel-based Virtual Machine) works directly at the hardware level, like a Type 1 hypervisor, using the virtualization capabilities of modern processors (like Intel VT or AMD-V). However, KVM also requires a host operating system (usually Linux) to run on, a characteristic of Type 2 hypervisors. Therefore, you can think of this alternative to Xen as a kind of hybrid hypervisor.

KVM supports various virtual hard disk formats, including QCOW2 and RAW. Additionally, it is possible to pass physical disks directly to a VM (pass-through). KVM is often used with management tools such as libvirt to simplify VM management. libvirt provides an API for controlling virtualization environments.

KVM also uses cgroups (control groups) Linux to monitor VM resource usage. This results in fine-grained management of CPU, memory, and I/O resources for each VM. You can also set quality of service (QoS) policies and bandwidth limits for network and storage resources to ensure that critical VMs are prioritized. Since KVM is directly integrated into the Linux kernel, it benefits from the security mechanisms and features available in the kernel, such as SELinux or AppArmor. These security modules include advanced access controls and protect VMs from potential threats.

Advantages of KVM over Citrix Hypervisor:

• Offers a complete virtualization environment in combination with QEMU and libvirt.
• KVM supports a wide variety of guest systems.

Disadvantages of KVM over Citrix Hypervisor:

• KVM does not have built-in high availability features.
• Its support is less extensive.

Microsoft Hyper-V

As a type 1 hypervisor, Hyper-V runs directly on the host hardware and is therefore very efficient at allocating resources. Hyper-V is compatible with a wide range of guest operating systems, including Windows (starting with Windows XP) and various Linux distributions and FreeBSD. The platform offers fine-grained CPU and memory management, including the allocation of dedicated or dynamic resources for VMs. The feature dynamic memory automatically adapts the working memory needs of VMs.

As for storage options, Hyper-V supports virtual hard disks (VHD and VHDX), direct allocation of physical disks (pass-through disks) and storage spaces. Live Migration Moves running VMs between physical hosts without downtime. With Hyper-V, storage migration is possible, allowing VHDs from a VM to be moved to another storage device while it is running.

A big advantage of Hyper-V is the ability to replicate VMs from one site to another, which improves failure safety and continuity. In addition, Hyper-V allows you to create snapshots and checkpoints that record the state of a VM at a given point in time and thus allow a quick rollback if necessary.

Advantages of Hyper-V over Citrix Hypervisor:

• Hyper-V is directly integrated into Windows Server and some Windows Desktop operating systems.
• Microsoft provides user-friendly management tools such as Hyper-V Manager and System Center Virtual Machine Manager.

Disadvantages of Hyper-V compared to Citrix Hypervisor:

• Hyper-V is limited to Windows-based host operating systems, such as Windows Server and some versions of Windows 10/11.
• Using Hyper-V in enterprise environments requires paid Windows Server licenses.
• Citrix hypervisor may be more stable during live migration in highly connected environments.

VirtualBox

VirtualBox is a versatile open source virtualization software from Oracle. This hypervisor type 2 is suitable for various versions of Windows (from XP to Windows 11), many Linux distributions like Ubuntu, Fedora and CentOS, as well as macOS and Solaris. The software has extensive networking options, including virtual network configuration such as NAT, Bridged and Host-Only. These options facilitate communication between virtual machines and with the physical network. VirtualBox also supports virtual switches and network interface cards.

You can copy an existing VM to quickly create an identical environment for testing or development purposes. For example, it is often useful to clone a base VM with all the necessary tools and settings to create different test environments. Another advantage of VirtualBox is the integration of Guest Additions. These special drivers and software extensions optimize the performance and functionality of virtual machines, including better graphics and smooth mouse integration.

Advantages of VirtualBox over Citrix Hypervisor:

• VirtualBox runs on different host operating systems such as Windows, macOS, and Linux, which provides greater flexibility in choosing the hardware environment.
• VirtualBox is aimed at both businesses and private users.
• The intuitive user interface and simple installation process are ideal when starting out with virtualization software.

Disadvantages of VirtualBox compared to Citrix Hypervisor:

• VirtualBox may perform less well than Citrix in large enterprise environments with large numbers of virtual machines.
• Compared to Citrix Hypervisor, VirtualBox lacks some advanced enterprise features such as advanced network configurations, built-in high availability and failover mechanisms.
• VirtualBox is less designed for scalability than Citrix, so larger environments can be a challenge.