How to analyze DNS load balancing

This article introduces you how to analyze DNS load balancing. The content is very detailed. Interested friends can use it for reference. I hope it will be helpful to you.

DNS (Domain Name System) domain name system is a service of the Internet. As a distributed database that maps domain names and IP addresses to each other, it can make people more convenient to access the Internet. DNS uses TCP and UDP port 53.

In this way, when we access a domain name, DNS looks up the corresponding distributed database, obtains the corresponding ip address of the domain name, and accesses the ip address from the internet.

Many people may wonder that this DNS seems to have nothing to do with the system architecture. So let's talk about the relationship between DNS and architecture.

In fact, the earliest implementation of load balancing function is the DNS mechanism.

First of all, explain a term, load balancing: in large network applications, it is common to use multiple servers to provide the same service. The method of evenly distributing the pressure on each server and dispersing the pressure is called load balancing.

Next, let's briefly analyze how DNS achieves load balancing:

The same name is configured for multiple domain name addresses in DNS, so the client that queries the domain name address will get one of the addresses, so that different customers can access different servers to achieve the purpose of load balancing. That is, website visitors are randomly assigned different IP. DNS load balancing is a simple and effective method, but it can not distinguish the differences between servers, nor can it reflect the current running state of the server.

For example, taobao has developed its own dns load balancer to handle high QPS. For some small and medium-sized companies can use third-party services, such as DNSPod and so on.

This is the end of the analysis on how to carry out DNS load balancing. I hope the above content can be helpful to you and learn more knowledge. If you think the article is good, you can share it for more people to see.