Nacos cluster partition

In fact, the concept of cluster partitioning also appeared in previous Eureka, such as:

eureka:client:fetch-registry: falseregister-with-eureka: falseservice-url:defaultZone: http://localhost:8888/eureka# What is this defaultZone, why use this name?Why use this form to declare the registry?

In a distributed application, instances of the same service may be started on different machines and locations. For example, our user management service may have one server deployed in Chengdu and one server in Chongqing.At this time, we have started the borrowing service on the server in Chengdu. If our borrowing service wants to call the user service now, we should give priority to the user service in the same area to call, which will make the response faster.

Therefore, we can partition the services deployed in different computer rooms, and we can see that the partition of the instance is the default:

We can modify it directly in the configuration file:

spring:application:name: borrowservicecloud:nacos:discovery:server-addr: localhost:8848# Modify to the cluster in Chongqing areacluster-name: Chongqing

Of course, since we are using different startup configurations here, it is also possible to add the environment variable spring.cloud.nacos.discovery.cluster-name directly to the startup configuration, hereWe allocate one area for both user service and book service, and the borrowing service is configured as the Chengdu area:

After the modification is completed, let's try to restart it (Nacos will also restart) and observe the cluster distribution in Nacos:

You can see that there are now two clusters and one instance is running.We then called the borrowing service, but found that the call was not prioritized according to the region, and the load balancing call in the round-robin mode was still used.

We must provide Nacos's load balancing implementation to enable the region-priority invocation mechanism, just modify it in the configuration file:

spring:application:name: borrowservicecloud:nacos:discovery:server-addr: localhost:8848cluster-name: Chengdu# Enable nacos support of loadbalancer and integrate Nacos load balancingloadbalancer:nacos:enabled: true

Now we restart the borrowing service, and we will find that users and book services in the same region are called first. Now we can offline the service in Chengdu:

You can see that after going offline, since there is no service available in this area, the borrowing service will call the user service in the Chongqing area.

In addition to calling according to the priority of the region, the instance in the same region can also set the weight separately. Nacos will give priority to the instance with the larger weight to call. We can configure it directly on the management page:

Or configure it in the configuration file:

spring:application:name: borrowservicecloud:nacos:discovery:server-addr: localhost:8848cluster-name: Chengdu# The size of the weight, the greater the priority, the default is 1weight: 0.5

By configuring weights, some less-performing machines can be used less, and more of those instances on better-performing hosts are used.