KVM is the Kernel-based Virtual Machine for short, it is an open source system virtualization module, since Linux 2.6.20 is integrated in each major release of Linux. It uses Liux own scheduler to manage, so relative to Xen, the core source code rarely. KVM has become one of the mainstream VMM academia. KVM requires hardware virtualization support (Intel VT technology, such as technology or AMD V). It is completely hardware-based virtualization. The early Xen is based on Para-Virtualization, a new version of the software simulation is based on full hardware support for virtualization. But Xen province has its own process scheduler, memory management module, so the code is relatively large. Widely spread flow of business systems virtualization software VMware EAX series is software-based simulation Full-Virtualization.
Because of the relatively cumbersome process management, RedHat has released an open source project libvirt. libvirt has a command-line tool also APl, can be done to manage virtual machines through a graphical interface. Most complete management platform to manage virtual machines through kvm libvirt; for example Openstack, Cloudstack, OpenNebula and so on.
concept:
Simulation software advantages: can simulate any hardware, including the absence of disadvantages: is very effective against, for general research, different production environments. Representatives: QEM
The virtualization layer translation software full virtualization paravirtualization --- --- VMware virtual machine changes to the kernel (linux) xen (to be eliminated) full hardware support for virtualization --- KVM
Container virtualization docker
1. Classification virtualization hardware virtualization hardware virtualization representatives: KVM 2. software virtualization representatives: Qemu
Note: Hardware virtualization support is needed cup, if the cpu does not support it can not create a KVM virtual machine. Qemu and KVM biggest difference is that the underlying physical machine oh a direct memory 4G, create a virtual machine vm allocate memory for 4G, also in the creation of a sub-4G. Overweight supports, but does not support qemu
KVM Centos7 been built into the system kernel, no need to install