What is the relationship between Domain0 and VRM?

Hello, friend!

What is Domain 0?

Domain 0: is a modified Linux Kernel. It is the only virtual machine running on top of the Xen Hypervisor. It has access to physical IO resources and interacts with other virtual machines running on the system. Domain0 needs to be in other domains. Starting before startup, it is the virtualized policy implementer. Domain0 is used to capture and process the IO information of Domain U and the underlying hardware interaction.

If you want to know more information about Domain 0, see What is Domain 0 and its function?

What is the relationship between Domain0 and VRM?

Domain 0 is not necessarily associated with VRM.

VRM does not know the existence of Domain0, and Domain0 does not know the existence of VRM. VRM manages VMs by sending traffic to the VNA on the CNA host. The VNA then invokes the corresponding components. Even if Domain0 is replaced with the KVM architecture, VRM can manage VMs in the KVM architecture without any modification.

Hope this helps!

Domain0: is a modified Linux Kernel. It is the only virtual machine running on top of the Xen Hypervisor. 

It has access to physical IO resources and interacts with other virtual machines running on the system. Domain0 needs to be in other domains. Starting before startup, it is the virtualized policy implementer. Domain0 is used to capture and process the IO information of domainU and the underlying hardware interaction.

CNA is a virtualized operating system that can virtualize the underlying physical hardware resources into virtual resources for use by upper-layer virtual machines.

Hypervisor: It is an intermediate software layer between the operating system and the hardware. It is responsible for CPU scheduling and memory allocation between virtual machines. It not only abstracts the hardware of the virtual machine, but also controls the command execution of each virtual machine; however, it will not handle network IO, as it is the executor of virtualization.

DomainU: All paravirtualized virtual machines running on the Xen Hypervisor are called "Domain U PV Guests", which runs an operating system with a modified kernel.

Domain0

Xen virtualization environment with domain (Domain) to describe various virtual machines, each domain has its own ID and other properties, thus each virtual machine is often expressed Domain 0 , Domain. 1 and the like, may be used a shorthand way, as the dom0 . Dom0 is a unique virtual machine running on Xen Hypervisor . Its operating system kernel is a specially modified Linux kernel, which can directly access hardware I/O resources and interact with other virtual machines. Other domains do not have direct access to hardware I/O resources and are highly isolated from each other. Therefore, dom0 is also called a privileged domain, and other domains are collectively called DomU (Unprivileged Domain) . It should be noted that DomU implements I/O functions through Dom0 . Therefore, Dom0 must be started before DomU runs

DomainU

DomU is a non-privileged domain, and they have no right to directly access hardware resources. Xen supports two different types of virtualization modes: PV (Paravirtualization) and HVM (Hardware-assisted or Full Virtualization) , which can run on the same Xen Hypervisor at the same time , and can even use PV technology in the HVM environment , which is also called PV on HVM .

Xen Hypervisor is an intermediate software layer that runs between a physical server and an operating system. It allows multiple operating systems and applications to share a set of basic physical hardware, so it can also be regarded as a " meta " operating system in a virtual environment . It can coordinate access to all physical devices and virtual machines on the server, also called Virtual Machine Monitor ( Virtual Machine Monitor ). Hypervisor is the core of all virtualization technologies. The ability to support multi-workload migration non-disruptively is the basic function of Hypervisor . When the server starts and executes the Hypervisor , it allocates an appropriate amount of memory, CPU , network, and disk to each virtual machine, and loads the guest operating system of all virtual machines.