Sentinel Traffic Guard

Note: This chapter is a little confusing and clear.

After the previous study, we learned about the avalanche problem of microservices, that is to say, if a microservice has a problem, it may cause the entire link to be directly unavailable. In this case, we need to make timelyThe circuit breaker and downgrade, these strategies, we previously implemented by using Hystrix.

SpringCloud Alibaba also has its own microservice fault tolerance component, but it is more powerful than Hystrix.

With the popularity of microservices, stability between services and services has become increasingly important.Sentinel uses traffic as the entry point to protect the stability of services from multiple dimensions such as traffic control, circuit breaker downgrade, and system load protection.

Sentinel has the following characteristics:

• Rich application scenarios: Sentinel has undertaken the core scenarios of Alibaba's Double Eleven for nearly 10 years to promote traffic, such as spikes (that is, burst traffic is controlled within system capacity)Tolerable range), message shaving peaks and valleys, cluster flow control, real-time fuse downstream unavailable applications, etc.

• Complete real-time monitoring: Sentinel also provides real-time monitoring capabilities.In the console, you can see the second-level data of a single machine connected to the application, and even the aggregated operation of a cluster with a scale of less than 500.

• Extensive open source ecosystem: Sentinel provides out-of-the-box integration modules with other open source frameworks/libraries, such as integration with Spring Cloud, Apache Dubbo, gRPC, Quarkus.You only need to introduce the corresponding dependencies and perform simple configuration to quickly access Sentinel.At the same time, Sentinel provides native implementations of multiple languages ​​such as Java/Go/C++.

• Complete SPI extension mechanism: Sentinel provides an easy-to-use and complete SPI extension interface.You can quickly customize logic by implementing extension interfaces.For example, custom rule management, adaptation of dynamic data sources, etc.