KVM

Definition

KVM, which stands for Kernel-based Virtual Machine, is a virtualization technology built into the Linux kernel that allows the kernel to function as a hypervisor. This enables multiple virtual machines (VMs) to run on a single physical host, each with its own operating system and resources. KVM turns the Linux kernel into a type-1 hypervisor, making it capable of handling multiple guest operating systems efficiently and securely.

5 Must Know Facts For Your Next Test

1. KVM is included in the mainline Linux kernel since version 2.6.20, making it widely available and supported across various distributions.
2. It utilizes hardware virtualization features provided by modern CPUs, such as Intel VT-x and AMD-V, which improve performance by offloading virtualization tasks to the hardware.
3. Each KVM guest runs as a regular process on the host, which helps in resource management and allows for easy monitoring using standard Linux tools.
4. KVM supports live migration, meaning VMs can be moved between physical hosts without downtime, which is crucial for load balancing and maintenance.
5. The KVM ecosystem includes management tools like libvirt, which provides an API for managing VMs and resources in a consistent manner across different hypervisors.

Review Questions

• How does KVM utilize Linux kernel features to provide virtualization services, and what benefits does this bring?
  • KVM takes advantage of the existing architecture of the Linux kernel by leveraging its scheduling, memory management, and security features to create virtual machines. This integration allows for better performance and resource utilization compared to traditional hypervisors. Since KVM operates as part of the kernel, it can efficiently manage resources while maintaining isolation between VMs, which enhances security and stability.
• Compare KVM with traditional hypervisors in terms of performance and resource management capabilities.
  • Unlike traditional hypervisors that run as separate applications above the operating system, KVM operates directly within the Linux kernel. This unique architecture allows KVM to benefit from optimized performance due to direct access to hardware resources. Additionally, because KVM treats each VM as a standard Linux process, it inherits the resource management capabilities of the Linux kernel, making it easier to control CPU usage, memory allocation, and I/O operations efficiently.
• Evaluate the impact of KVM's support for live migration on system administration and cloud environments.
  • KVM's capability for live migration significantly impacts system administration by enabling seamless VM relocation without downtime. This feature is essential in cloud environments where workload distribution and maintenance tasks must occur without disrupting services. Live migration facilitates efficient resource utilization and enhances load balancing across servers, ultimately leading to improved availability and reliability in cloud infrastructures.

Related terms

Hypervisor: A hypervisor is software that creates and runs virtual machines, allowing multiple operating systems to share a single hardware host.

QEMU: QEMU is an open-source emulator and virtualizer that works in conjunction with KVM to provide virtualization capabilities, enabling full system emulation.

VirtIO: VirtIO is a set of standardized interfaces for virtual devices in KVM, enhancing performance by providing efficient data transfer between the guest and host systems.