Relationship between xen hypervisor and domain0

Source: Internet
Author: User
Tags xen hypervisor

The "xen domain" is defined in "xen virtualization" as follows:

Xen domain is a specific instance of a xen virtual machine running on a specific physical piece of hardware.

Domain is an instance of the xen virtual machine running on the physical hardware. In general, xen is a virtual machine instance virtualized by xen. Do not forget that xen is a software that allows you to create and manage virtual machines. "Xen" is a virtual machine software, just as we usually say that a virtual machine is VMware. Because virtual machines are the product of xen virtualization, not the xen itself.

For domain, "xen virtualization alization" also says:

Xen supports two basic types of domains with different uses and capabilities.

This indicates that domain is the product of xen virtualization, while domain0 is the most special product of xen virtualization. It is particularly mentioned later.

Xen has the ability to virtualize virtual machines, so there are related methods to manage these virtual machines.

The "xen memory zation" statement says:

Xen Manages access to memory and hardware resources through a combination of its hypervisor and a specially privileged xen-modified kernel that is used to manage, monitor, and administer all other xen virtual machines running on a specific piece of hardware. this
Specially privileged xen kernel is known as domain0.

As mentioned above, xen uses hypervisor and domain0 to manage access to memory and hardware resources.

Both hypervisor and domain have access to management memory and hardware resources. However, the virtual machine that needs to access memory and hardware resources is naturally used, so it achieves the goal of managing other virtual machines. The management function of domain0 is special.

So what are the specific management of these two things? How is division of labor managed?


In "xen memory zation:

One of the goals of xen has always been to separate implementation requirements from policy decisions, leaving administrative and configuration options to the domain0 system rather than hardwiring them into the hypervisor. loe-level CPU and memory allocation
And Management is done by the hypervisor because this is a physical requirement for running multiple virtual machines on a single physical system. the hypervisor is responsible for creating, managing, and deleting the virtual network interfaces and virtual
Block devices associated with each guest domain.

The above means that "xen separates policy formulation from policy implementation, and transfers management and configuration work to domain0, rather than giving management and configuration work to hypervisor for implementation ". The translation is stubborn. In general, "Virtual Machine Management is divided into two categories: determining how to manage, and implementing after determining management. Domain0 performs the first class, and hypervisor performs the second class ." That is to say, we can set management parameters for virtual machines in domain0. hypervisor sets virtual machines according to the parameters set in domain0.

This is the relationship between hypervisor and domain0.

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