Nacos registry is divided into server and client. The server is written in Java, which provides registration discovery service and configuration service for clients. The client can be implemented in multiple languages. The client is nested with microservices. Nacos provides sdk and openApi. If there is no sdk, you can manually write the logic of service registration, discovery and configuration pull according to openApi.
Nacos service domain model is mainly divided into namespace, cluster and service. As can be seen from the hierarchical storage model in the figure below, in the service layer, settings such as health check switch, metadata, routing mechanism and protection threshold are saved, while in the cluster, data such as health check mode, metadata and synchronization mechanism are saved, and in the instance, data such as ip, port, weight, health check status, offline status, metadata and response time are saved. The function of these data will be discussed in Chapter 3.
Service registration method: Take Java nacos client V 1.0. 1 as an example. The strategy of service registration is to send a heartbeat to nacos server every 5 seconds, and the heartbeat carries information such as service name, service ip and service port. At the same time, nacos server will also initiate health check to the client actively, supporting tcp/:
Firstly, two dependencies of springcloud, alibaba-nacos-config and alibaba-nacos-discovery, are tools to combine nacos clinet with the cloud, and 0.2.x corresponds to Spring Boot 2.x.x, 0. 1.x corresponds to Spring Boot1.x.x. These two components can be combined with various versions. Exclude nacos-clinet dependencies and introduce the version of nacosclinet you want to introduce, as shown below:
Add the configuration of the configuration center on bootstrap.properties
Add the following configuration in application-xxx.properties
If the springboot startup class does not have the @EnableDiscover annotation, please add it.
After making the above changes, you can register/configure the service with Nacos.
Demo:
Feign and Ribbon can be used, so I won't introduce them here.
Ordinary application parameters can be directly configured in the configuration center. If you need a configuration that can be refreshed dynamically, you need to add the @RefreshScope annotation to the corresponding class. Examples are as follows. When the configuration is changed in nacos configuration center, the value of method getId will also be refreshed.
Configuration center parameter modification/setting
As shown in the following two figures: Select the corresponding namespace at the top of the configuration management-configuration list of nacos console, click the plus sign in the upper right corner of the list to add a configuration, and the data ID is the project name -{spring.profiles.active}. Property, if no group is specified in bootstrap.properties, fill in DEFAULT_GROUP to describe the configuration, and fill in properties format or Yaml format for the configuration content.
Select a service click detail in the service management-service list in the console, and you can see an online/offline button in the cluster list below. Click it to perform online/offline operations on this instance without requesting an offline instance.
You can control traffic by manually configuring weights. When there are two instances in the cluster, the higher the weight, the more requests reach that instance.
The initial value of the weight is 1.
The range of protection threshold is 0~ 1.
Health proportion of service = number of healthy instances of service/total number of instances.
When the service health ratio
When the service health is >; When the threshold is protected, only healthy instances will be returned to the caller.
Select a service in the Service Management-Services list and click Details to configure it.