Everything is designed to solve some problem, and so is cloud computing. So what is cloud computing, and what problems can it solve? Before looking at cloud computing, let’s take a look at what’s wrong with the growth of the traditional IT industry, and explore the nature of cloud computing and why IT is happening.

I. Enterprise demands in the traditional IT era

In the traditional IT era without cloud, if enterprises want to do things in the IT industry, they need to purchase servers, install hosts, pull network cables, buy hard disks and a series of operations. Time consuming and energy consuming, the whole cycle is very long, and a series of bottlenecks will be encountered in subsequent expansion and online services.

The whole deployment process of traditional IT is: purchase of hardware — secure deployment of software — business test and launch — maintenance. When purchasing hardware, it is difficult to assess the capacity required by the business. If the hardware is purchased too much, it will be wasted; if the hardware is purchased too little, it will encounter bottlenecks in the future when the business grows. Moreover, the utilization rate of hardware is also low. Many specific hardware resources can only use specific software, such as Web server, Oracle server, SAP server, etc. It is ok if the utilization rate of these servers with specific software is high, but if the utilization rate is low, it is really a waste of hardware. Hardware maintenance is time-consuming and laborious. The maintenance scope is scattered and the maintenance period is long.

A typical example is that if the traditional IT industry is compared to a snack stand, IT is necessary to buy a barbecue, a venue, tables and chairs, and waiters to open a snack stand. It’s ok to open a barbecue stand, but if it’s a chain, SKR will be tired.

Later, due to the expansion of business, many enterprises do not want to be limited by the traditional hardware mode, so they will share their internal resources in their own, and gradually the earliest private cloud began to appear. Before we talk about private clouds, let’s talk about how these resources and so on can be shared, breaking down a set of constraints.

The concept of virtualization and logic

Virtualization refers to using virtualization technology to virtualize a computer into multiple logical computers. Running multiple logic computers on one computer at the same time, each logic computer can run different operating systems, and applications can run in independent space without affecting each other, thus significantly improving the efficiency of the computer.

For example, if a server (computer) compared to a building, before a building can only do a business, the utilization rate of the building is not high all depends on this business is good, if the business is not good, then the floor in many places without guests, the utilization rate is very low, resulting in a waste of resources. Virtualization is to divide the building into many floors or rooms, which can be rented to different people to do different businesses (divided into different logical computers, install different operating systems, run different businesses), do not interfere with each other, different storefronts called virtual machines VM (that is, logical computers).

1. Logical computing resources (virtualization)

Computing virtualization refers to abstracting the CPU of a host for use by VMS. The CPU is the “brain” of a computer, responsible for computing and other functions. Virtualizing the CPU means that the “brain” robot can be divided into many “smaller heads” and calculate different things at the same time without interfering with each other. If you put a computer with two cpus, each of which has 30 cores, you have a total of 60 cores. You might only need 10 cores in a daily calculation, and most of them are wasted. After virtualization is used, the vm can be divided into multiple VMS and assigned to different VMS.

2. Storage logic (virtualization)

Storage is like a warehouse, used to access goods (data, documents, etc.) in a building. Generally, when a store wants to do business, the store only keeps a small part of the goods, and most of the goods are stored in the warehouse, and can be transferred when there is a need. Of course, the way to transfer goods is different, that is, and storage unicom will be different, here not in detail. This traditional way of warehouse storage will have some problems, such as traffic jam (IO bottleneck, network delay) and other factors, it may be very difficult to transfer goods, resulting in various wastes. And, different warehouses correspond to different storefronts, some storefronts have more things and some things are less, and some warehouses will be “idle”.

Storage virtualization means that all storage resources (warehouses) are managed in a centralized manner to form a storage resource pool (similar to a wholesale market) that does not correspond to stores. Instead, all resources are stored in a centralized manner for stores (computers) to use.

3. Logical network resources (virtualization)

A network is a network of all physical devices and media (optical cables, cables, etc.). In the absence of virtualization, networking was mostly a matter of different physical machines. When a physical machine is virtualized, its routers, firewalls, network loads, and switches are virtualized. Therefore, the communication between virtualized resources depends on network virtualization. For example: between two storefronts (VMS), through network virtualization is in the building, channel, door, intersection, etc., so that the room between a building can realize communication. Network virtualization not only achieves internal interconnection and isolation, but also external interconnection and isolation.

Such a public road is very convenient, but there are many security risks. Many corporate things are not in a public area, can only be accessed through the internal road. A typical example of network virtualization is VPN technology, which quietly builds a private road over these public highways for use in specific situations.

4. What is clustering

What if you have 20 VMS on a physical machine, and one day those VMS need more resources, or you need more VMS? This is where the concept of clustering comes in. Cluster refers to the deployment of multiple physical machines together to integrate resources, which can be interconnected and invoked. Just like Wang Jianlin bought a business district, the building of this business district is his, as long as it is his name of the shop, where want to use how many resources or want to move to where, you can move at any time. The migration can be seamless while the business is running on the VM. Just like a shop, there are customers all the time, but it doesn’t matter, we have technology to realize, so that the shop can be relocated without closing, without affecting any situation inside.

The emergence of this technology brings a lot of convenience, for example, when a building suddenly catches fire (physical machine down), the shops inside can be immediately moved to another building (HA monitoring function); When there are not many guests in each building at night, we can move to one building, and the other buildings will not operate, which can save water, electricity and resources (DPM distributed power principle).

5. A private cloud

The cloud virtualizes all traditional resources to maximize efficiency and utilization. If an enterprise has multiple data centers, it can use SDN (software defined Network). And integrate them on the network to form a unified cloud data center with disaster recovery and backup functions.

Third, the emergence of public clouds

The integration of resources within an enterprise enables resources within the enterprise to be shared. This is called a private cloud. Then, there are specialized public cloud enterprises that integrate all traditional resources for other enterprises to use. Just like Grandpa Wang Jianlin’s business district, they suddenly stopped opening their own shops and rented them out for others to use. Cloud computing is a product of simplified IT operation and maintenance, platformization of resources and servitization.

The introduction of Iaas/Paas/Saas

Before there was no cloud, want to open a shop to do business, what to buy and build, land, buildings, all kinds of materials and so on. With the advent of cloud services, there is relatively little trouble. Public cloud services are divided into three tiers: Iaas, Paas, and Saas.

Iaas: Infrastructure as a Service

If a public cloud enterprise leases its own hardware resources, such as servers, it provides Iaas services. If an enterprise uses Iaas services, it does not need to purchase hardware. However, it needs to install, deploy, and develop operating systems by itself. For example, if a person wants to run a business, he can rent a shop without taking care of anything in these buildings, but the shop needs to be decorated by himself, and water and electricity need to be handled by himself. If you open the public cloud official website of a large cloud vendor, you can view Iaas services such as elastic cloud server, dedicated cloud, storage service (dedicated and object), cloud hard disk, virtual private network, and elastic load balancer (ELB).

PaaS: platform-as-a-Service

Paas, sometimes called middleware, provide a platform that enterprises can use directly. For example, a person to rent a store, the store’s water and electricity, decoration and other things have all been done, the purchase channel has also been provided, the user only needs to arrange their own simple store, decide what business the store does. Paas services on public cloud vendors generally include message sending service, image recognition service, etc. These services have been built and can be directly developed on the platform enterprises.

SaaS: software-as-a-Service

Software is a little bit easier to understand, and we use software every day. Just like a person doing business, what he cares about is whether he can make money or not. We provide many ready-made shops and staff for him, so he can invest in renting and selling shops according to his needs and types, so as to maximize his own interests. Some Saas services, such as cloud security services, are Saas services, which directly provide a very complete software service that has been developed.

The following is a picture of the three levels of service downloaded from the Internet, hoping to help you understand.



At the end, so do you see what cloud computing really is?


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