KVM vs OpenStack: What are the differences?

KVM and OpenStack are two widely used technologies in cloud computing. While KVM is a hypervisor that enables the virtualization of hardware resources, OpenStack is an open-source cloud computing platform that provides a complete infrastructure-as-a-service (IaaS) solution. Here are the key differences between them.

1. Architecture: KVM is a standalone hypervisor that runs directly on the host operating system, whereas OpenStack is a complete cloud management platform composed of several components, including a hypervisor like KVM, networking, storage, and orchestration services. OpenStack provides a unified interface to manage and control various virtualization technologies, including KVM.

2. Scalability: KVM offers scalability by allowing the creation of multiple virtual machines (VMs) on a single physical host. However, its scalability is limited to the capabilities of the host hardware. OpenStack, on the other hand, provides horizontal scalability by allowing the deployment and management of VMs across a cluster of physical hosts. This allows for the creation and scaling of large-scale cloud infrastructures.

3. Management and Orchestration: KVM primarily focuses on the virtualization of hardware resources and does not have extensive management and orchestration capabilities on its own. OpenStack, being a complete cloud management platform, includes powerful management and orchestration features. It provides APIs and services for provisioning, scaling, and managing the entire cloud infrastructure, including VMs, networks, and storage.

4. Resource Sharing: In KVM, the virtual machines are generally isolated and dedicated to specific users or applications. On the other hand, OpenStack allows for resource sharing among multiple users or tenants. This enables the creation of multi-tenant environments where resources can be allocated and shared dynamically based on user or application requirements.

5. Integration and Ecosystem: KVM is a widely adopted hypervisor and can be integrated with various management tools and solutions. However, its ecosystem is mainly focused on the virtualization layer. OpenStack, being a comprehensive cloud computing platform, has a vast ecosystem of plugins, extensions, and integration options with other cloud technologies and services. It provides a flexible and extensible framework for building and integrating various cloud-related solutions.

6. Community and Support: KVM has a strong community of users and contributors, with active development and support. However, OpenStack has a much larger and thriving community due to its broader scope and popularity. OpenStack benefits from the contributions and expertise of various organizations and individuals, ensuring continuous development, improvement, and support for the platform.

In summary, KVM is a hypervisor that focuses on virtualization, while OpenStack is a complete cloud management platform with extensive management and orchestration capabilities. KVM is suitable for small-scale virtualization deployments, while OpenStack is a preferred choice for building and managing large-scale cloud infrastructures.