Spring Cloud, Eureka FAQ Summary

In Spring Cloud, Eureka FAQ Summary.

1eureka.environment: Specifying the environment

Reference Documentation:

1eureka.datacenter: Specify Data center

Reference documentation: Using configuration items:

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Eureka.instance.leaseRenewalIntervalInSeconds

Reference Documentation:

123Why is it so Slow to Register a Service? Being An instance also involves a periodic heartbeat to the registry (via the client's Serviceurl) with default duration 3 0 seconds. A service is not available for discovery by clients until the instance, the server and the client all have the same Metada Ta in their local cache (so it could take 3 heartbeats). You can change the period using eureka.instance.leaseRenewalIntervalInSeconds and this would speed up the process of gettin G clients connected to other services. In production it's probably better to stick with the default because there is some computations internally in the server That's assumptions about the lease renewal period.

Translation:

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As an instance, it also involves a periodic heartbeat with the registry, with a default duration of 30 seconds (via Serviceurl). The service is not available for client discovery (so it may take 3 heartbeats) until the instance, server, and client have the same metadata in the local cache. You can use the Eureka.instance.leaseRenewalIntervalInSeconds configuration, which speeds up the process of connecting clients to other services. In production, it is best to stick to the default values because there are some calculations inside the server that make assumptions about the renewal.

If you see this hint on the first page of Eureka Server, the Eureka has entered protection mode.

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emergency! EUREKA may incorrectly claiming INSTANCES is up when the they ' RE not. Renewals is LESSER THAN THRESHOLD and HENCE the INSTANCES is not BEING EXPIRED JUST to be SAFE.

Protected mode is primarily used for protection in a network partition scenario between a group of clients and Eureka Server. Once in protected mode, Eureka server will attempt to secure the information in its service registry and no longer delete the data in the service registry (that is, it will not unregister any microservices).

See: During the development process, we often expect Eureka server to be able to kick out closed nodes quickly and efficiently, but novice users often encounter problems with Eureka server not kicking off a closed node due to the Eureka Self-protection mode and the long heartbeat cycle. Here's how to fix it:

(1) Eureka Server side: Configure the time interval to turn off self-protection and configure Eureka server to clean up invalid nodes on demand.

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eureka.server.enable-self-preservation# set to False to turn off self-protection Eureka.server.eviction-interval-timer-in-ms # cleanup interval (in milliseconds, Default is 60*1000)

(2) Eureka client: Configure the Health Check to open and configure the renewal and expiration times as needed.

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eureka.client.healthcheck.enabled# Open Health Check (requires Spring-boot-starter-actuator dependency) eureka.instance.lease-renewal-interval-in-seconds# Renew Update interval (default 30 seconds) Eureka.instance.lease-expiration-duration-in-seconds # Renewal Expiry time (default 90 seconds)

Example:
Server-side configuration:

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Eureka:server:enable-self-preservation:false eviction-interval-timer-in-ms:4000

Client Configuration:

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Eureka:client:healthcheck:enabled:true instance:lease-expiration-duration-in-seconds:30 Lease-renewal-interval-in-seconds:10

Attention:
Changing the Eureka Update frequency will break the server's self-protection capabilities, and it is not recommended to customize these configurations in a production environment.
See: In spring Cloud, the default value for the instance ID of the service is ${spring.cloud.client.hostname}:${spring.application.name}:${spring.application.instance_id:${server.port}} , that is 机器主机名:应用名称:应用端口 . So the information that you see in the Eureka Server home page is similar to the following: itmuch:microservice-provider-user:8000 . What if you want to customize this part of the information?

Example:

eureka:  client:    serviceUrl:      defaultZone: http://localhost:8761/eureka/  instance:    preferIpAddress: true    instance-id: ${spring.cloud.client.ipAddress}:${server.port}        # 将Instance ID设置成IP:端口的形式

eureka.client.healthcheck.enabled=trueShould only be set in Application.yml. If the settings in BOOTSTRAP.YML will cause some undesirable side effects, such as the name of the app registered in Eureka is unknown, and so on.

Transferred from: http://www.itmuch.com/spring-cloud-sum-eureka/

Spring Cloud, Eureka FAQ Summary