Advantages of micro service registry Nacos over Eureka

Why use a registry

Have used ip:port Development experience of address direct call service ？ The painful experience is omitted here 500 word ......, The disadvantages of this method ：

• You need to manually maintain all service access ip Address list .
• A single service needs to be built by itself to achieve load balancing , For example, using nginx Load balancing strategy , Or deploy a single service based on containerized multiple instances , Load balancing between instances .
• Service providers ： Provide service access to the registry based on the service name ip:port And other information .
• Registry Center ： According to service name , Store the corresponding ip:port And other information .
• Serving consumers ： Obtain the name of the calling service from the registry according to the service name ip:port And other relevant information sets , Then get the final server according to the load balancing policy ip：port Access address .

Use springcloud when , What is commonly used is eureka and nacos As a registry , How to choose ？（nacos eureka Project case fhadmin.cn）

Service providers

Actively register with the registry , The contract , Offline , Get registry . After successful service registration , Send heartbeat to the registry regularly , Ensure that the service is not eliminated .

Registry Center

Storage service instance , Scan the registry regularly , Eliminate expired service instances . High availability through synchronous replication , Get the registry first , Then register yourself with other registries , Belong to AP Pattern . In the actual project , According to the environment , for example dev,test,prod Configure different registry clusters , If different projects use a unified registry , It can only be distinguished by service name .

Let's focus on Eureka Self-protection mechanism . If a large number of service instances expire, they will be rejected , Then the registry enters self-protection mode , The information in the registry is no longer deleted , The aim is to improve eureka The usability of . By default , The failure rate of heartbeat is calculated at 15 Is it less than in minutes 85%, If lower 85%,Eureka Server These instances will be protected , Keep these instances from expiring .

Tell me about a painful online experience , The error is described as follows ：

At that time, the service deployment was successful , stay Eureka The registry has shown that the service has been registered successfully , however , When the front-end request is forwarded to the service through the gateway , There has been no response , The service call has been unsuccessful .nginx forward , Gateway forwarding is confirming where the problem is , After many torments , Directly through the gateway ip The address is forwarded to the online service , Quickly solve the problem . follow-up , replay , should Eureka Self-protection mechanism , Resulting problems . The service registered in the registry is an unavailable service , however , Due to the self-protection mechanism ,Eureka Server Invalid services are not eliminated .

The subsequent solution is , Set up enableSelfPreservation=false Turn off self-protection , hold renewalPercentThreshold Proportion reduction , stay Eureka Server End , If there is an invalid service, the service will be rejected .

nacos Registry Center

nacos yes springcloud An extension of , The registry function is through NacosDiscoveryClient Inherit DiscoveryClient, stay springcloud in , And Eureka It can switch without intrusion . The registry can manually remove service instances , Notify the client to update the cached instance information through a message

nacos The key point is to understand its domain model Nacos Data model Key Uniquely determined by triples , Namespace Namespace , grouping group,service service . Please refer to the official website for details Nacos framework .

nacos And Eureka The comparative advantages are as follows ：

• nacos In automatic or manual offline service , Use the message mechanism to notify the client , Changes to service instances respond quickly ;Eureka Invalid services can only be eliminated through task timing .
• nacos According to namespace Namespace ,DataId,Group grouping , To distinguish between different environments （dev,test,prod）, Configuration of different projects .