Load balancing on Tencent cloud

1. Nginx produce ~

Nginx Same as Apache It's the same Web The server . be based on REST Architectural style , To unify resource descriptors （Uniform Resources Identifier）URI Or uniform resource locator （Uniform Resources Locator）URL As a basis for communication , adopt HTTP The protocol provides all kinds of network services .

However , At the beginning of the design, these servers were limited by the environment at that time , For example, the scale of users at that time , network bandwidth , Product features and other limitations and their positioning and development are not the same . It also makes each Web Servers have their own distinct characteristics .

Apache It's a long time , And it's the undisputed world's largest server . It has many advantages ： Stable 、 Open source 、 Cross platform and so on .

It's been around too long , When it rose , The Internet industry is far from what it is now . So it's designed to be a heavyweight .

However, it does not support highly concurrent servers . stay Apache Running tens of thousands of concurrent accesses on , Will cause the server to consume a lot of memory .

The switching between processes or threads by the operating system also consumes a lot of CPU resources , Lead to HTTP The average response speed of requests is reduced .

It's all decided Apache It can't be high performance Web The server , Lightweight high concurrency server Nginx And that's what happened .

Russian engineers Igor Sysoev, He's doing it for Rambler Media During work , Use C Language development Nginx.

Nginx As Web The server has always been Rambler Media Provide excellent and stable service . so what ,Igor Sysoev take Nginx Open source code , And license free software .

Based on the following ：Nginx became angry

1. Nginx Using a Event driven architecture , So that it can support millions of levels of TCP Connect .
2. High modularity and free software license make third-party modules emerge in endlessly （ This is an open source era ）.
3. Nginx It's a Cross platform server , Can run in Linux、Windows、FreeBSD、Solaris、AIX、Mac OS On the operating system .
4. The stability of these excellent designs .

Nginx Where it comes in handy

About agents

1. When it comes to agency , First of all, we need to define a concept , The so-called agency is A representative 、 One channel ; It's about Two roles , One is the represented role , One is the target character .
2. The process by which the delegated role accesses the target role to complete some tasks is called the agent operation process ; It's like a boutique in life , Guests arrive adidas The store bought a pair of shoes , This store is the agent , The represented role is adidas manufacturer , The target role is the user .
3. In short , Namely adidas The boss came to the franchised store to sell shoes to the guests .

Forward agency ： The legendary “ Over the wall ”

Before talking about reverse proxy , Let's first look at the forward agent , Positive agency is also the most commonly encountered agency mode , We will talk about the processing mode of forward agent from two aspects , Respectively from the software and life to explain what is a positive agent .

In today's Network Environment , If we need to because of technology Visit some foreign websites , At this time, you will find that there is no way for us to access a website located abroad through a browser .

At this time, you may use an operation FQ Visit ,FQ The main way is Find a proxy server that can access foreign websites , We send the request to the proxy server , Proxy server to visit foreign websites , Then pass the accessed data to us ！

The above-mentioned agent mode is called forward agent , The biggest feature of forward proxy is that it is very forward Specify the server address to access ;** The server only knows which proxy the request comes from , It's not clear from which specific client ;** Forward proxy mode shields or hides real client information .