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KVM and VMware
What is KVM
KVM (for Kernel-based Virtual Machine) is a complete virtualization solution for Linux on x86 hardware, including virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, kvm.ko, and a processor-specific module, kvm-intel.ko or kvm-amd.ko, which provides the core virtualization infrastructure.
Using KVM, you can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has its own virtualized hardware: network card, disk, graphics adapter, etc.
KVM is open source software. Since 2.6.20, the kernel components of KVM are included in mainline Linux. Since 1.3, the userspace components of KVM are included in mainline QEMU.
Blogs of people active in KVM-related virtualization development are available athttps://planet.virt-tools.org/Jointly published
Using KVM open source virtualization technology, we can turn the Linux kernel into a hypervisor that can be used for virtualization.
After migrating to a KVM-based virtualization platform, we can easily enhance, inspect, and modify our hypervisor source code as it is open source. Therefore, we can customize the hypervisor as per our requirements. Moreover, KVM is very easy to deploy and use as it is built into the Linux kernel.
What is VMware
VMware is an American company that provides cloud computing and hardware virtualization software and services. It is the first company to virtualize the x86 architecture and achieve commercial success. The company was founded in 1998 and is headquartered in Palo Alto, California, USA.
VMware provides the ESXi hypervisor and the vSphere virtualization platform. These virtualization technologies allow us to configure and create virtual machines (VMs). Thus, we can modernize our infrastructure to control and deliver new and legacy applications. Next, VMware ESXi is a bare metal hypervisor that is installed directly onto a physical server. This will help us consolidate our hardware.
If we use VMware vSphere, we need VMware's control stack to manage our virtual machines. There are several licensing rights levels available.
How to choose the right hypervisor?
1. Scalability
If the requests and number of guest machines increase, KVM is able to scale to meet the demand load. The most demanding application workloads can be virtualized using KVM. It is the basis of many enterprise virtualization setups, such as private clouds and data centers.
KVM was very easy to extend and integrate to meet our needs as it gave us access to its source code and was highly interoperable with existing infrastructure.
VMware provides a scalable virtualization platform, but this needs to be considered when adding more hosts, as VMs may affect the Enterprise License Agreement (ELA). vSphere provides up to 12TB of RAM per host and up to 64 hosts per cluster. In addition, we can use the multiple application programming interfaces (APIs) provided by vSphere to manage our VMS more easily.
2. Performance
KVM and ESXi are both type 1 hypervisors and should perform better than type 2 hypervisors.
According to the SPECvirt_sc2013 benchmark, KVM runs applications at near-native speeds and is faster than other industry hypervisors. Although ESXi is generally much slower to boot and create servers than KVM. In addition, ESXi also performs slower when running servers, but this difference may not be a problem for typical workloads.
3. Cost
KVM is a part of the open source operating system, so it is completely free. To use VMware, we need to purchase licenses for various products and services, and these licenses will be locked into the Enterprise License Agreement (ELA). Therefore, the total cost of ownership of KVM is lower.
4. Maturity
Both KVM and ESXi are stable and mature hypervisors capable of supporting enterprise workloads.
5. Integration
To communicate with the host's physical hardware, different hypervisors use different methods. ESXi uses VMware's management platform. So we need to use other products in VMware's control stack. Therefore, this will increase our hardware requirements.
Because KVM is an open source product, it can integrate with any existing infrastructure and many different Windows and Linux platforms without the same limitations.
6. Support
With KVM, we will need to rely on support from the open source community and our own IT organization. With VMware, we will get enterprise-grade support because it is part of the ELA.
Summary
Compared with VMware, KVM is considered a better choice because it has the ability to support physical and virtual infrastructure for enterprise workloads with lower operating expenses. In addition, KVM also has advantages such as excellent performance, no vendor lock-in, lower total cost of ownership, open source advantages, cross-platform interoperability, existing functions of Linux operating system, and simplicity of migration of a single virtualization platform, creating, pausing, stopping, starting and template hundreds of virtual machines on hundreds of other hardware or software.
