7 Best Free Open-source Hypervisors

If you are thinking of implementing virtualization on your system, you need to get a hypervisor package. Open-source hypervisors provide a path to getting this technology for free. Be aware that some open-source systems are difficult to set up and a bit clunky because they don’t have the big development budgets that commercial virtualization providers enjoy. So, we wrote this list to provide a guide on which free open-source hypervisors are worth considering.

Here is our list of the best free open-source hypervisors:

1. KVM (Kernel-based Virtual Machine) Integrated into Linux, KVM transforms the kernel into a hypervisor. It supports hardware virtualization and allows users to run multiple virtual machines, each with its own Linux or Windows operating system.
2. Xen Project A powerful hypervisor that supports both paravirtualization and hardware virtualization. Xen is widely used in cloud environments, offering robust isolation and security features, making it suitable for enterprise-grade virtualization solutions.
3. QEMU A versatile emulator and virtualizer, QEMU can run guest systems without hardware assistance. It supports multiple architectures and integrates with KVM for enhanced performance, allowing for a wide range of virtualization scenarios.
4. VirtualBox Originally developed by Sun Microsystems, VirtualBox offers a user-friendly interface and supports various operating systems. It’s ideal for desktop virtualization, providing features like snapshots, seamless mode, and shared folders for easy management.
5. OpenVZ A container-based virtualization solution for Linux, OpenVZ allows multiple isolated Linux containers to run on a single physical server. It offers efficient resource management and is commonly used in web hosting environments.
6. Proxmox VE A complete open-source virtualization management solution, Proxmox VE combines KVM and LXC for virtual machines and containers. Its web-based interface simplifies management, while built-in backup and clustering features enhance usability.
7. oVirt A powerful virtualization management platform, oVirt is built on top of KVM. It offers a web interface for managing virtual machines, storage, and networks, providing a robust environment for enterprise virtualization.

What is a Hypervisor?

A hypervisor is a software layer that enables the creation and management of virtual machines (VMs) on a physical host. It allows multiple operating systems to run concurrently on a single hardware platform by abstracting and allocating resources such as CPU, memory, and storage.

Hypervisors can be categorized into two types: Type 1, which is a bare-metal hypervisor that runs directly on the host hardware, and Type 2, which is a hosted hypervisor that runs on a conventional operating system. Type 1 hypervisors, like XenServer and VMware ESXi, typically offer better performance and efficiency, making them ideal for enterprise environments.

What Does Open-Source Mean?

Open-source refers to software whose source code is made publicly available for anyone to view, modify, and distribute. This model encourages collaboration and transparency, allowing developers and users to contribute to the software’s improvement.

Free Hypervisors

Open-source hypervisors are particularly valuable for organizations seeking cost-effective virtualization solutions without vendor lock-in. Users can customize the hypervisor to meet specific needs, troubleshoot issues more effectively, and benefit from community-driven support and enhancements.

You will notice that most of these options are variations on a single technology – KVM. This is because KVM is probably the most solid open-source system available but it isn’t very easy to use, so these other options have started up to provide better interfaces for that system.

The Best Free Open-Source Hypervisors

1. KVM (Kernel-based Virtual Machine)

KVM is an integrated part of the Linux kernel, turning it into a hypervisor. It allows for the creation and management of virtual machines, utilizing hardware virtualization features of modern CPUs. KVM is widely adopted for both server and desktop virtualization due to its performance and scalability.

Key Features:

• Integration with Linux: Directly part of the Linux kernel, providing efficient performance and resource management.
• Guest OS Support: Compatible with a variety of operating systems, including various Linux distributions and Windows.
• Hardware Virtualization: Utilizes Intel VT-x and AMD-V technologies for enhanced performance.
• Live Migration: Allows running VMs to be moved between hosts without downtime, facilitating maintenance and load balancing.
• Advanced Networking: Supports Virtio and other advanced networking options, enhancing network performance and efficiency.

Why do we recommend it?

KVM is highly efficient and versatile, making it suitable for both personal and enterprise-level virtualization needs. Its integration with Linux offers excellent performance and resource management, while its active community ensures continuous improvement and support.

I found that this system enables organizations to consolidate workloads efficiently while maximizing hardware utilization. Its capabilities allow users to run multiple virtual machines, each isolated from one another. This enhances security and provides flexibility in deploying various applications, making it a top choice for virtualization on Linux systems.

Who is it recommended for?

KVM is recommended for system administrators, developers, and enterprises looking for a robust and flexible virtualization solution. Its open-source nature makes it ideal for those who prefer customizable solutions and want to leverage existing Linux infrastructure.

KVM requires a modern Linux distribution with a kernel version of 2.6.20 or newer. It supports various guest operating systems, including various versions of Windows and Linux. You can find more details and download instructions on the KVM website.

2. Xen Project

The Xen Project is a powerful hypervisor that enables the virtualization of multiple operating systems on a single hardware platform. Renowned for its robustness, it supports both paravirtualization and hardware virtualization, making it a popular choice for enterprise environments and cloud computing.

Key Features:

• Paravirtualization and Hardware Virtualization: Supports both techniques, allowing flexibility in deployment.
• Isolation: Strong isolation between VMs enhances security and stability, making it ideal for cloud environments.
• Live Migration: VMs can be moved between physical hosts without downtime, improving resource management.
• Flexible Networking: Provides advanced networking capabilities tailored to enterprise needs.

Why do we recommend it?

Xen Project is ideal for users requiring high performance and security. Its extensive isolation capabilities make it suitable for cloud environments where multi-tenant architectures are prevalent, ensuring that resources are shared without compromising security.

I noted that Xen’s architecture allows for efficient resource allocation and management, making it suitable for large-scale deployments. With its capability to run on various hardware platforms, it empowers organizations to optimize their infrastructure while enhancing flexibility and performance across multiple workloads.

Who is it recommended for?

Xen is recommended for enterprises and service providers that need a reliable and secure virtualization platform. It’s particularly beneficial for those managing large data centers or cloud environments requiring robust isolation and resource management.

Xen runs on x86 and ARM architectures, requiring a supported Linux distribution. It supports multiple guest OS options, including Windows, Linux, and BSD variants. For installation and details, visit the Xen Project website.

3. QEMU

QEMU is an open-source emulator that provides hardware virtualization and system emulation. It is highly versatile and can run multiple architectures, making it an excellent choice for testing and development. When combined with KVM, it delivers near-native performance for virtual machines.

Key Features:

• Architecture Emulation: Capable of emulating multiple hardware architectures, making it versatile for various applications.
• Live Migration: Supports migrating running VMs between hosts without downtime, enhancing flexibility.
• Integration with KVM: When combined with KVM, it delivers near-native performance for virtual machines.

Why do we recommend it?

QEMU‘s flexibility in supporting multiple architectures and its ability to run without hardware virtualization make it a unique tool. This versatility is particularly beneficial for developers needing to test software across various platforms without physical hardware.

I learned that this service enables efficient emulation and virtualization, making it suitable for development environments, testing, and even production. Its powerful capabilities allow users to run different operating systems on diverse hardware, enhancing testing scenarios for cross-platform applications and system configurations.

Who is it recommended for?

QEMU is ideal for developers, testers, and IT professionals needing a flexible virtualization solution. It is particularly useful for those working with multiple architectures or requiring system emulation for software development and testing.

QEMU runs on various platforms, including Linux, Windows, and macOS, and supports numerous guest operating systems, including Windows and various Linux distributions. For download and more information, visit the QEMU website.

4. VirtualBox

VirtualBox is a user-friendly, open-source virtualization solution originally developed by Sun Microsystems and now run by Oracle. It allows users to run multiple operating systems simultaneously on a single machine. Known for its simplicity and extensive features, VirtualBox is popular among developers and testers for its ease of use.

Key Features:

• Cross-Platform Support: Runs on Windows, macOS, and Linux, supporting a variety of guest OSs.
• User-Friendly Interface: Intuitive GUI that simplifies the creation and management of VMs.
• Snapshot and Clone Features: Allows users to save VM states and create duplicates for testing.

Why do we recommend it?

VirtualBox‘s intuitive interface and powerful features make it perfect for beginners and advanced users alike. Its ability to run various guest OSs without extensive configuration makes it an ideal tool for developers and educators seeking a straightforward virtualization solution.

I discovered that this hypervisor provides a seamless experience for running virtual machines. Its snapshot feature allows users to save the state of a VM at any point, making it easy to revert changes or experiment without risks. This flexibility is crucial for testing and development environments.

Who is it recommended for?

VirtualBox is recommended for individual users, educators, and developers who need an accessible virtualization tool. Its ease of use and extensive documentation make it suitable for those new to virtualization or those requiring a reliable testing environment.

VirtualBox runs on Windows, macOS, and Linux, supporting a wide range of guest operating systems, including various Windows versions and Linux distributions. For download and installation details, visit the VirtualBox website.

5. OpenVZ

OpenVZ is an operating-system-level virtualization solution for Linux. It allows multiple isolated Linux containers to run on a single physical server, efficiently sharing resources while maintaining separation. OpenVZ is particularly favored in hosting environments for its lightweight and efficient design.

Key Features:

• Container-Based Virtualization: Runs multiple isolated Linux containers on a single physical server.
• Resource Sharing: Efficiently shares resources between containers, optimizing server utilization.
• Strong Isolation: Provides strong separation between containers, enhancing security.

Why do we recommend it?

OpenVZ offers a highly efficient way to run multiple Linux environments on a single server. Its lightweight containers make it ideal for hosting providers and developers looking for resource-efficient virtualization without the overhead of traditional hypervisors.

I observed that this hypervisor enables users to efficiently manage multiple Linux environments, enhancing server utilization while providing strong isolation. Its container-based architecture allows for rapid deployment of applications and services, making it a popular choice in shared hosting and cloud computing.

Who is it recommended for?

OpenVZ is recommended for hosting providers, developers, and organizations seeking to optimize resource use while maintaining isolation. It’s particularly suited for environments where multiple Linux instances need to run simultaneously without the overhead of full virtualization.

OpenVZ runs on Linux and requires a compatible kernel version. It supports Linux-based guest operating systems, making it a streamlined choice for those focused on Linux environments. For more details and downloads, visit the OpenVZ website.

6. Proxmox VE

Proxmox VE is an open-source virtualization management platform that integrates KVM for virtual machines and LXC for containers. With a powerful web interface, it simplifies the management of virtualized environments, making it suitable for both enterprise and home lab setups.

Key Features:

• Integrated KVM and LXC: Combines full virtualization with container-based virtualization for flexibility.
• Web-Based Management Interface: Provides a comprehensive dashboard for managing VMs and containers.
• Backup and Restore Functionality: Built-in tools for easy VM backups and restorations.

Why do we recommend it?

Proxmox VE‘s combination of KVM and LXC allows for versatile virtualization options, making it a powerful tool for managing diverse workloads. Its user-friendly interface and robust features cater to both beginners and experienced users looking to optimize their virtual environments.

I noticed that this tool streamlines virtualization management, offering features like live migration, backups, and clustering capabilities. Its ability to run both VMs and containers on a single platform makes it an ideal choice for organizations seeking flexibility and ease of management in their virtualization strategy.

Who is it recommended for?

Proxmox VE is recommended for system administrators, businesses, and enthusiasts who need a comprehensive virtualization solution. Its powerful features and ease of use make it suitable for both production environments and home labs.

Proxmox VE runs on x86_64 hardware and requires a 64-bit processor with virtualization support. It supports various guest operating systems, including Windows and Linux. For installation instructions and downloads, visit the Proxmox VE website.

7. oVirt

oVirt is an open-source virtualization management platform built on KVM. It provides a comprehensive web-based interface for managing virtual machines, storage, and networks. oVirt is designed for enterprise environments, enabling users to create and manage complex virtual infrastructures efficiently.

Key Features:

• Web-Based Dashboard: Provides a comprehensive interface for managing VMs, storage, and networking.
• KVM Integration: Built on KVM, offering robust virtualization capabilities with enterprise features.
• Advanced Storage Management: Supports various storage types, enhancing data management and performance.

Why do we recommend it?

oVirt’s robust management capabilities and seamless integration with KVM make it a powerful tool for enterprise virtualization. Its rich feature set, including storage management and live migration, allows organizations to optimize resources effectively.

I found that this system enhances the virtualization experience by providing a complete management solution for KVM-based environments. Its intuitive interface simplifies tasks like VM provisioning, monitoring, and management, making it suitable for organizations looking to streamline their virtual infrastructure.

Who is it recommended for?

oVirt is recommended for enterprises and IT departments seeking a comprehensive virtualization management platform. It’s particularly useful for organizations with complex infrastructures that require advanced management capabilities and resource optimization.

oVirt requires a compatible Linux distribution with KVM support and runs on x86_64 hardware. It supports various guest operating systems, including Linux and Windows. For installation and download details, visit the oVirt website.