Preface: Learn the basic concepts of cloud computing, and sort out the basic knowledge outline.
Table of contents
Characteristics of Cloud Computing
The development of cloud computing
Core Technology of Cloud Computing
Common Virtualization Technologies
Features of server virtualization technology
Memory multiplexing technology
cloud computing concept
What is cloud computing? The introduction of Baidu Encyclopedia is as follows:
"Cloud" is essentially a network. In a narrow sense, cloud computing is a network that provides resources. Users can obtain resources on the "cloud" at any time, use them according to demand, and can be regarded as unlimited expansion. You can pay according to the amount of use. "Cloud" is like a water plant. We can receive water at any time, and there is no limit. According to the water consumption of our own home, we can pay the water plant.
In a broad sense, cloud computing is a service related to information technology , software , and the Internet . This kind of computing resource sharing pool is called "cloud". Cloud computing gathers many computing resources and realizes automatic management through software. With the participation of fewer people, resources can be provided quickly. In other words, as a commodity, computing power can be circulated on the Internet, just like water, electricity, and gas, which can be easily accessed and relatively cheap.
Cloud Computing - Search (bing.com)
For cloud computing learning, I recommend the Alibaba Cloud community. There are many good articles in the community.
Cloud Computing-Articles-Alibaba Cloud Developer Community-Technology-Alibaba Cloud (aliyun.com)
Characteristics of Cloud Computing
On-demand self-service
Cloud computing allows users to configure computing power, storage, network and other resources according to their needs, and can manage and monitor them independently at any time.
Fast Elastic Scaling
Cloud computing provides the ability of elastic computing resources to quickly and automatically expand or shrink according to user needs to achieve efficient utilization and cost control. Users can quickly increase or decrease computing resources according to demand without waiting or paying high fees.
Cloud computing can quickly and automatically provide applications with additional computing, storage and network resources to meet instantaneous, very large load requirements, and then automatically reduce resources to save costs.
Resource pooling
Cloud computing centrally manages and allocates the computing, storage and network resources of multiple customers to maximize resource utilization and efficiency. Specifically, cloud computing integrates the computing needs of multiple users into the same resource pool by virtualizing a large number of physical resources to achieve efficient utilization and sharing.
Users do not need to know the specific physical location and configuration, but manage and control computing resources through the cloud service provider's management platform.
metered service
Cloud computing users can monitor and measure their usage through various tools and services, which is convenient for users to monitor their own resource usage, and to know the overall situation based on resource usage.
extensive network access
Cloud computing allows users to configure computing power, storage, network and other resources according to their needs, and can manage and monitor them independently at any time.
deployment mode
Private Cloud
The private cloud mainly provides cloud services for the enterprise organization and is not open to the public.
public cloud
Public clouds are generally available over the Internet . May be free or low cost. In a public cloud, users don't know which other users share and use resources with them, how the entire platform is implemented, or even control the actual physical facilities.
community cloud
The core feature of the community cloud is that the cloud servers deployed on the cloud are only used by employees in two or more specific organizations , and other people and organizations have no right to rent and use cloud server resources. Units and organizations participating in the community cloud have common requirements, such as cloud service model, security level, etc. Organizations with business relevance or affiliation are more likely to build community clouds, because on the one hand, they can reduce their own costs, and on the other hand, they can share information.
hybrid cloud
Hybrid cloud refers to public cloud + private cloud , that is, the enterprise's IT is divided into two parts and deployed on two clouds respectively.
Industry cloud
A cloud platform that is established and maintained by an organization that plays a leading role or has key resources in the industry or a certain region, and provides paid or unpaid services to the industry or related organizations and the public in an open or semi-open manner, such as financial cloud, Government cloud, medical cloud, health cloud, etc.
recommended reading
Community Cloud of Four Deployment Modes of Cloud Server - Zhihu (zhihu.com)
service mode
I found a picture on the Internet, which shows the three service modes very vividly.
Three Service Modes
Explanation of terms in Baidu Encyclopedia
IaaS
IaaS (Infrastructure as a Service), that is, infrastructure as a service. Refers to a service model that provides IT infrastructure as a service through the network and charges users based on the actual usage or occupancy of resources.
PaaS
PaaS is the abbreviation of (Platform as a Service), which refers to Platform as a Service . The business model that regards the server platform as a service, and the corresponding server platform or development environment provided as a service in the era of cloud computing becomes PaaS (Platform as a Service).
SaaS
Software operation service (Software as a Service, referred to as SaaS) enables users toconnect and use cloud - based applications through the Internet . Common examples are e-mail , calendars , and office tools. [2] It does not require users to install the software product on their own computers or servers.
The development of cloud computing
Since the 1950s, with a history of more than 70 years, Baidu Encyclopedia has introduced the development process of cloud computing in detail.
Cloud computing (scientific term)_Baidu Encyclopedia (baidu.com)
Core Technology of Cloud Computing
virtualization technology
Virtualization technology is the core technology of cloud computing. What is virtualization technology?
Virtualization technology refers to the abstraction and transformation of various physical resources of a computer ( CPU, memory, disk space, network adapter, etc.), which can be divided and combined into one or more computer configuration environments.
The following article is well written and recommended reading!
In-depth understanding of virtualization - Zhihu (zhihu.com)
Virtualization
What is virtualization?
Virtualization refers to freedom from physical constraints
Common Virtualization Technologies
Virtualization technology is divided into: server virtualization, storage virtualization, network virtualization, application virtualization.
Server virtualization
Hypervisor is the core of virtualization technology
In the form of software, a virtual environment that is exactly the same as the physical host environment is realized, with all the resources of the physical host, including CPU, memory, network IO, device IO, etc., which is equivalent to isolating the resources of the physical host for the upper layer use.
Mainstream Hypervisor
VMware ESXi
Microsoft Hyper-V
Linux KVM (open source)
Citrix XenServer
Bare Metal Technology
Bare metal virtualization, directly installs virtualization software on the hardware, and then installs the operating system and applications on it, relying on the virtualization layer kernel and server console for management.
What is "bare metal"? _bisal(Chen Liu)'s Blog - CSDN Blog
Features of server virtualization technology
Partition
isolation
Encapsulation and easy migration
Relative to hardware independent
storage virtualization
CPU
Basic concepts of Socket, CPU, Core, Thread, hyperthreading
Socket is a card slot with single-way and double-way
Core refers to the number of cores
Thread includes: thread, hyperthreading, hyperthreading core number = core number * 2
vcpu corresponds to the number of threads
Multicore vs hyperthreading, multicore faster than hyperthreading blocks (one dual core vs single core dual threads)
recommended reading
Detailed explanation of CPU working mode, multi-core, hyper-threading technology - Zhihu (zhihu.com)
NUMA affinity calls
Overscaling means that the total number of resources required by virtualization exceeds the total number of resources on physical machines.
resource requisition
memory virtualization
memory overallocation
The memory starts from physical address 0, and the memory is contiguous
How memory works
recommended reading
4.1. Basic principles of memory virtualization | Code Farm (codenong.com)
Memory multiplexing technology
cpu-memory-hard disk
copy-on-write memory sharing
memory replacement
Memory bubble resource requisition ballom releases idle virtual machine memory to virtual machines with high memory usage
tools
recommended reading
Elastic computing service ESC
example
An instance is a virtual computing environment , consisting of CPU, memory, system disk, and running operating system; ESC instance is the core concept of cloud server, other resources, such as disk, IP, image, snapshot, etc., can only be combined with ESC It is meaningful to use.
region
how to choose? Select the region where the customer is located
Cloud servers in different regions cannot communicate with each other on the intranet
availability zone
Cloud servers in different availability zones can communicate with each other on the intranet
mirror image
type
Public Mirror Custom Mirror Shared Mirror Mirror Marketplace
disk
storage
system disk
data disk
snapshot
Snapshots are not backups
A fully usable copy of the data is a copy of the data that the data can represent
read, write, rollback, delete
Data source volume copy-before-write snapshot volume
mapping table
The more snapshots, the slower the performance
redirect on write
cow pow
Three kinds:
Consistent snapshots : CPU-memory-hard disk tools (virtual machine tools)
Memory snapshot: slow, memory size, rollback-boot hard disk
Ordinary snapshot: block, complete instantly, rollback-shutdown Instant clone may lose data and memory data that has not landed on the hard disk
Dedicated network VPC
network virtualization
free
security group ACL
Each ECS instance must be added to at least one security group
two ports
TCP：22 TCP：3389
Security Group Authorization Whitelist Blacklist
ENI
Primary NIC Secondary NIC
Label
Identify resources for easy identification
To be continued...