About the author: A cloud computing network operation and maintenance personnel, sharing network and operation and maintenance technology and useful information every day.
Public account: Netdou Cloud Computing School
Motto: Keep your head down and be respectful
Personal homepage: Internet Bean’s homepage
write in front
This series will continue to update the study of cloud computing Alibaba Cloud ACA, to understand the basic knowledge of cloud computing and network security related industries, as well as the use and deployment of Alibaba Cloud products. Improve personal understanding of cloud computing product technology.
Alibaba Cloud Computing Assistant Engineer Certification (ACA - Alibaba Cloud Certification Associate) is a professional technical certification for the use of Alibaba Cloud's basic products. It mainly involves Alibaba Cloud's core products of computing, storage, network, cloud database, and security. It is for students A comprehensive examination and competency certification to master the technical skills of Alibaba Cloud's main products. It is mainly aimed at students and developers. It can also be used as an entry certificate for operation and maintenance personnel.
Early review
Cloud Computing – ACA Learning Data Center Overview
Cloud Computing - ACA Learning Cloud Computing Overview
Cloud Computing - ACA learns the core technology of cloud computing
Cloud Computing - ACA Learning Cloud Computing Classification
Cloud Computing - ACA learns cloud computing architecture
Cloud Computing - ACA Learning Alibaba Cloud Cloud Computing Service Overview
Cloud Computing - Overview of ACA Learning Virtualization Technology
Introduction to this issue
In addition to KVM, there are many mature solutions for virtualization solutions, including XEN, VM, hyperV, etc.
This issue explains how to understand the concepts related to virtualization products through KVM virtualization solutions and other virtualization solutions, and master the basic concepts and content of virtualization products.
1. KVM virtualization solution
1.KVM Overview
KVM stands for Kernel-based Virtual Machine, a kernel-based virtual machine. KVM is a full virtualization solution using hardware virtualization technology.
- Developed by Quramnet and acquired by Red Hat in 2008.
- Support X86 s390 powerpc and other CPUs
- It has been included in the Linux kernel as a module since Linux 2.6.
- Requires a CPU that supports virtualization extensions
- Completely open source
2.KVM development milestones
2. Overview of KVM functions
When kvm was born, it was positioned as a full virtualization implementation based on hardware virtualization support. After it is loaded in the form of a kernel, it turns the Linux kernel into a hypervisor, but hardware management is still completed through the Linux Kernel. So he is a typical Type 2 Hypervisor.
- One KVM client corresponds to one process
- Each vCPU corresponds to a thread under the process
- Hardware devices are emulated by QEMU
- QEMU intercepts the operation and converts it to the actual physical device driver operation.
KVM features
- Memory management: Linux memory management mechanisms, such as large pages, KSM, NUMA, and inter-process shared memory through mmap, can be applied to client memory management.
- Storage and guest image formats: KVM is able to store virtual machine images using any storage supported by Linux, local disks with IDE, SCSI, SATA, network attached storage, SAN with iscsi and fiber channel support.
- Live migration: KVM supports live migration, transferring real running clients between hosts without interrupting service.
- Performance: KVM's outstanding virtualization performance in CPU, memory network and other aspects is mostly above 95% of the native system.
3. KVM development status and future trends
KVM has become the mainstream Hypervisor choice for openstack users
After 10 years of continuous development and evolution, KVM has become very mature. Its next development is as follows
- Large-scale deployment challenges (high concurrency)
- Real-time challenges
- There is room for further enhancement of security
- Performance tuning
4. Other virtualization solutions
In addition to KVM, there are other relatively mature virtualization solutions, as follows:
1.XEN
The emergence of xen predates KVM, dating back to the 1990s
Xen is a new open source project developed by the Computer Laboratory of the University of Cambridge in the United Kingdom. It is a software layer that can run directly on computer hardware rather than in the operating system. It can also run multiple guest operating systems (GuestOS) on computer hardware at the same time. It has received great promotion in the open source community.
Xen supports x86, x86-64, Itanium, Power PC and ARM processors, so it can run on many computing devices. At this stage, Xen supports common operating systems such as Linux, NetBSD, FreeBSD, Solaris, and Windows. Xen is a typical Type 1 Hypervisor in terms of architecture, which is different from KVM. There is no concept of a host, but the hardware is managed by the Xen Hypervisor (VMM)
XEN virtualization type - full virtualization
Full virtualization, also known as "Hardware Virtualization" (HVM), virtual machines running in a virtual environment always feel that they are running on hardware and are not aware of the virtualization technology of other virtual machines running in the same hardware environment.
In a fully virtualized virtual machine running on the XEN hypervisor, the operating system is a standard operating system. Unchanged operating system version, providing special hardware equipment. Required for XEN virtualized Windows virtual machines.
2.The development process of VMware
VMware is the leader in server virtualization. In recent years, its product series has been continuously enriched and its business processes have developed rapidly.
VMware was founded in 1998. Since its beginning as a provider of server computing virtualization technology solutions, it has developed three key businesses: software-defined data center, hybrid and multi-cloud computing, and end-user computing. It is a leader in cloud computing. The company's development can be divided into three key nodes.
2.1 VMmare representative products
VMware has a very complete product line, including PaaS products and IaaS products; there are products running on Linux platforms, as well as products on Windows and Mac platforms.
VMware Workstation
VMware Workstation is a desktop-level virtualization product that runs on Windows, Linux and Mac operating systems and is a Type 2
Hypervisor.
VMware ESXi
VMware ESXi is server-level virtualization software. Unlike Workstation, it runs directly on the hardware platform and is a Type1 Hypervisor.
3.Hyper-V
Hyper-V is Microsoft's server virtualization product. Microsoft used virtual machine management technologies such as Vmware ESXi and Citrix Xen for the first time. This means that Microsoft will compete more directly with market leader VMware, but it will still be different.
Hyper-V is a hypervisor virtualization technology proposed by Microsoft that can realize desktop virtualization. Hyper-V is initially planned to be released at the same time as Windows Server 2008 in the first quarter of 2008. Hyper-V Server 2012 has completed the release of the RTM version.
hyper-V architecture
HyperV is similar to Xen in architecture. It is also a Type 1 Hypervisor. Hyper-V adopts a microkernel architecture, taking into account security and
performance requirements.
The underlying Hypervisor of Hyper-V runs at the highest privilege level, which Microsoft calls ring-1 (and Intel calls it
root mode), while the OS kernel and driver of the virtual machine run in ring 0, and the application runs Under ring 3, this architecture does not need to use complex BT (Binary Privileged Instruction Translation) technology, which can further improve security.
4.Container
Strictly speaking, Container containers are not a major category of virtualization software. Containers are not a certain virtualization software, but a general term for a certain type of software, including Docker and LXC.
In addition, containers are not a hardware platform-level virtualization technology, but a software operating environment virtualization technology. It is an operating system-level virtualization technology.
The birth of Linux Container container technology (in 2008) solved the problem of "container transportation" in the IT world. Linux Container (LXC for short) is a kernel lightweight operating system layer virtualization technology. Linux Container is mainly implemented by two major mechanisms: Namespace and Cgroup.
container technology
Container technology uses cgroup, namespace and other mechanisms provided by the Linux kernel to isolate applications.
Namespace
Namespace is also called namespace, which mainly does access isolation. The principle is to abstract a type of resource and encapsulate it together for use by a container. For this type of resource, because each container has its own abstraction and they are invisible to each other, it can Achieve access isolation.
Of course, the role of the container is to pack and isolate the goods, so that the goods of company A and the goods of company B are not mixed, otherwise the unloading will not be clear. Then Namespace also has the same function, isolation
Cgroup
Cgroup is a control group, also known as a control group. It is mainly used for resource control. The principle is to place a group of processes in a control group, and by allocating specified available resources to this control group, the purpose of controlling the resources available to this group of processes is achieved.
Isolation alone is not enough, we also need to manage the resources of goods. Similarly, shipping terminals also have such a management mechanism: what specifications and sizes of containers should be used for goods, how many containers should be used for goods, which goods should be transported first, how to suspend transportation services in case of extreme weather, how to change waterways, etc.. Universal, The corresponding Cgroup is responsible for resource management and control, such as restrictions on the use of CPU/MEM by the process group, priority control of the process group, suspension and recovery of the process group, etc.
Container technical features
Compared with the hardware configuration abstraction layer virtualization hypervisor technology, the characteristics of containers are very obvious. Traditional virtualization (virtual machine) technology is not only troublesome to deploy environments and applications, but also very troublesome for the portability of APP applications. For example, migrating a vm virtual machine in vmware to KVM is relatively cumbersome. However, it is very simple to have container technology. Container technology mainly has the following characteristics:
