ubuntu virtualization virtualization preface

There are currently three technologies for virtualization on linux, as follows
quote

OPENVZ: This platform is the cheapest VPS platform and has the lowest price in every vps provider. OPENVZ itself runs on linux. It virtualizes a server into multiple instances where the operating system can be installed separately through its own virtualization technology. Each such entity is a VPS. From the customer's point of view, this is a virtual The server can be regarded as an independent server. The VPS virtualized by OPENVZ can only install the linux operating system, and cannot install the windows system, such as Centos, Fedora, Gentoo, Debian, etc. The inability to install the windows operating system is the first disadvantage of openvz. Users who need to use the windows platform cannot use the OPENVZ VPS. The second disadvantage of OPENVZ is that OPENVZ is not fully virtualized. Each VPS account shares the kernel of the host machine and cannot be modified individually. Fortunately, the vast majority of users do not need to modify the kernel at all, so this disadvantage can be ignored for most people. And this is also the advantage of openvz. This shared kernel feature makes openvz the most efficient, surpassing platforms such as KVM, Xen, and VMware. In the case of not overselling, openvz is the fastest and most efficient VPS platform.

KVM, Xen, VMware: These VPS platforms can be classified into one category. When virtualizing the host machine, they are completely virtualized. Each VPS example does not share the host machine kernel, and each is independent. Almost all operations All systems can be installed on these virtualized VPSs. Full virtualization makes VPS less efficient than OPENVZ on these platforms. But because of its complete virtualization, there is almost no mutual interference between VPS on the same host machine, while OPENVZ depends on whether the VPS is overbooked, if the openvz VPS is overbooked, the performance will be affected. If the openvz VPS on the same host machine abuses resources, it will affect the performance of other VPS. This feature of OPENVZ is very similar to that of virtual hosts. The virtual host is to completely share the resources of the virtual host host, and the performance of the virtual host is most affected by other virtual hosts on the same host. OPENVZ is much better than web hosting. VPSs on KVM, Xen, and VMware platforms are almost completely unaffected by other VPS accounts.

It can be seen from the above analysis that OPENVZ has the highest cost performance when it is not oversold: low price and high efficiency. But it is easily affected by other VPS of the same host machine. Of course, if you can accept virtual hosts, you can also use openvz VPS, because the impact between virtual hosts is great. Platforms such as KVM, Xen, and VMware are the future development direction of VPS. Because the independence of each VPS is better than that of OPENVZ, many hosting companies no longer provide OPENVZ VPS. But because OPENVZ is cheap, efficient, and fast, OPENVZ is still the most popular choice for low-cost VPS.


quote

1. About XEN and KVM

KVM is a fully virtualized solution. Virtualization functions can be implemented on computers with x86 architecture. But KVM requires the support of the virtualization function in the CPU, and can only run on the CPU with virtualization support, namely Intel CPU with VT function and AMD CPU with AMD-V function.

Xen is also a virtualization solution under Linux and will soon be built into the kernel. The implementation method of Xen is to run a kernel that supports Xen functions. This kernel works under the control of Xen and is called Domain0. After starting the machine with this kernel, you can use the qemu software on this machine to virtualize multiple systems.


Developed by the Israeli company Qumranet, KVM has been put into the Linux kernel by the Linux kernel organization, and the x86 processor it uses needs to contain at least one of the hardware-assisted virtualization technologies (Intel-VT or AMD-V).

Xen is an external Hypervisor program (virtual machine management program); it can control virtual machines and allocate resources to multiple clients. After KVM is written into the Linux kernel, it is estimated that Xen is difficult to be written into the kernel; another On the one hand, KVM is part of Linux and can use the usual Linux scheduler and memory management. This means that KVM is smaller and easier to use.

In addition, Xen supports both full and paravirtualization (requires modification of the guest operating system, and the modified guest operating system can have better performance), KVM does not currently support paravirtualization.

The disadvantage of Xen is that if you need to update the Xen version, you need to recompile the entire kernel, and, if you set it wrong, the system will not boot.
In comparison, KVM is much simpler. It doesn't require recompiling the kernel or making any changes to the current kernel, it's just a few .ko modules that can be loaded dynamically. It has a more compact structure and a smaller amount of code. So, there is less chance of error. And in some ways, the performance is better than Xen.



Therefore, based on

LINUX .

Guess you like

Origin http://10.200.1.11:23101/article/api/json?id=326690452&siteId=291194637