Table 1-1 Glossary

Abbreviations	English	Chinese	Acronyms
MicroServices	MicroServices	微服务	Microservices is a lightweight SOA architecture that is commonly used to describe a loosely coupled distributed architecture that is widely used in cloud applications and Internet applications.
Provider	Provider	服务提供者	The service of the called party in the microservice invocation relationship.
Consumer	Consumer	服务消费者	The service that invokes the initiator in the microservice invocation relationship.
Application	Application	应用	A logical entity that represents a software application that represents a computer software application that has business functions presented to the user. An application built with a microservice architecture typically consists of multiple microservices.
Instance	Instance	微服务实例	A minimal service and deployment unit for a microservice, usually corresponding to an application process.
IAM	Identity and Access Management	身份及权限管理	Responsible for maintaining the management level, user, role, authorization relationship, user organization and other information in the PaaS system. And carry out authorization and authorization checks.
AK/SK	AK/SK Key	AK/SK密钥	Access key/Secret key is a set of key pairs used for API authentication and access control.
Service	Service	服务	A service is a description of a functional object that is accessed on demand. In the application model, the service is generally oriented to the application. The application usage service needs to subscribe to the service first, then bind the service and use it. In some business scenarios, it may also need to pay according to usage.
Load Balance	Load Balance	负载均衡	When an application accesses a microservice with multiple instances, it involves routing load balancing. Load balancing policies can be configured through configuration files to support multiple load balancing routing policies such as random, round-robin, session hold, and response time based weights.
Rate limit	Rate limit	限流	When a resource becomes a bottleneck, the service framework needs to limit the access request of the consumer and start the flow control protection mechanism. Flow control is available on both the consumer and provider sides. On the service consumer side, the frequency of requests sent to a micro service provider can be limited; on the service provider side, the frequency of requests sent by each microservice consumer can be limited, or the total consumption of the service provider can be determined according to the resource consumption of the service provider. Request frequency limits to prevent services from crashing due to resource exhaustion.
Service Degrade	Service Degrade	降级	Service downgrade mainly includes two strategies: masked downgrade and fault tolerant downgrade: shielded downgrade refers to the decision of the operation and maintenance personnel/developers when the trigger condition of the outside world reaches a certain critical value. Or a service is forced to downgrade. Fault-tolerant degradation means that when non-core services are unavailable, business logic can be released for faulty services to ensure the operation of core services.
Fault tolarance	Fault tolarance	容错	Fault Tolerance is a processing strategy in the scenario where an exception occurs when a consumer accesses a service. After an exception occurs, the service framework automatically selects a new service route to invoke.
Circuit Breaker	Circuit Breaker	熔断	There is usually a dependency between microservices. The service invocation link may contain multiple microservices. If one or more service access delays in the link are too high, the request for the portal service will continue. Stacking, continue to consume more threads, io resources, and eventually the system bottleneck due to resource accumulation, resulting in more services unavailable, resulting in avalanche effect. The fuse mechanism is designed for the above scenario. When a target service responds slowly or a large number of timeouts occur, the service call is blown. For subsequent call requests, the target service is no longer called, directly returned, and resources are quickly released. The target service situation is improved and the call is resumed.
Isolation	Isolation	隔离	Service isolation is an anomaly detection mechanism. Common detection methods are request timeout, excessive traffic, and so on. The general setting parameters include the timeout period, the maximum number of concurrent requests, etc. When the timeout period or the maximum number of concurrent requests is exceeded, an exception is recorded and used to calculate the error rate and the number of error requests in the fuse mechanism.
Service Mesh	Service Mesh	网格服务	An infrastructure layer service. In the process of micro-service, developers need to solve the problems introduced by applications running in distributed networks, such as fault tolerance, current limiting, load balancing, registration discovery, monitoring, etc. Service Mesh acts as the L4/L7 protocol agent. The application solves the problems caused by micro-services.
Legacy	Legacy	遗留系统	A legacy system is a software system that is still running and in use, but has entered the aging phase of the software lifecycle.