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This article will explain in detail how to configure multiple network cards in SpringCloud Eureka. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

If there is no special configuration for multiple network cards, the 192.168.239.1 8080 seen above and its linked URL address are probably not a string.

What we want to achieve when configuring Eureka Client is that where 192.168.239.1 Eureka Client 8080 is shown above, the IP address and port number are displayed, and the host and port of its URL address are the same as the IP address and port number shown here. At the same time, in the case of multiple network cards, we can choose which network card Spring Cloud App wants to use.

In the article "Spring Cloud Network Card selection", a solution for multi-network card configuration is given:

Spring.cloud.inetutils.preferred-networks: 192.168.239.

Eureka.instance.prefer-ip-address:true

By setting these two properties, the value of the host of the URL address is the IP address we want.

By looking at the status.ftl file under the spring-cloud-netflix-eureka-server package, it is found that the text displayed is the id of instance.

${instance.id}

${instance.id}

So all we have to do is assign instance-id to ip:port:

Eureka.instance.instance-id:$ {spring.cloud.client.ipAddress}: ${server.port}

one

Spring.cloud.client.ipAddress, where did this come from? Look at the class HostInfoEnvironmentPostProcessor, which is the implementation of the EnvironmentPostProcessor interface:

@ Override www.1b23.com

Public void postProcessEnvironment (ConfigurableEnvironment environment

SpringApplication application) {

InetUtils.HostInfo hostInfo = getFirstNonLoopbackHostInfo (environment)

LinkedHashMap map = new LinkedHashMap ()

Map.put ("spring.cloud.client.hostname", hostInfo.getHostname ())

Map.put ("spring.cloud.client.ipAddress", hostInfo.getIpAddress ())

MapPropertySource propertySource = new MapPropertySource (

"springCloudClientHostInfo", map)

Environment.getPropertySources () addLast (propertySource)

}

At this time, the problem arises. If you set it this way, you will find that the content displayed is different from its link address. Through the caller, it is found that although the host and port displayed and the host and port in the connection address are obtained through InetUtils, the execution time is different and the context information is different.

First of all, for the execution time of HostInfoEnvironmentPostProcessor, please see Spring Boot # EnvironmentPostProcessor. Although we have configured spring.cloud.inetutils.preferred-networks: 192.168.239, the contents of this application.xml file have not been loaded at this time. When HostInfoEnvironmentPostProcessor executes, there is no such configuration in the context, so it is executing:

InetUtils.HostInfo hostInfo = getFirstNonLoopbackHostInfo (environment)

one

At that time, there was no spring.cloud.inetutils.preferred-networks in environment: 192.168.239. This configuration.

The eurekaInstanceConfigBean method in EurekaClientAutoConfiguration constructs and returns an EurekaInstanceConfigBean,EurekaInstanceConfigBean as follows:

Public EurekaInstanceConfigBean (InetUtils inetUtils) {

This.inetUtils = inetUtils

This.hostInfo = this.inetUtils.findFirstNonLoopbackHostInfo ()

This.ipAddress = this.hostInfo.getIpAddress ()

This.hostname = this.hostInfo.getHostname ()

}

At this point in time, the configuration in application.yml has been loaded, and the configuration file for spring boot has been loaded before the container is created. For more information, see Spring Boot # EnvironmentPostProcessor,spring.cloud.inetutils.preferred-networks: 192.168.239. Information is already available, so this configuration will take effect, thus selecting an IP address that may not be the same as before.

Conclusion

Eureka Settin

Eureka.instance.prefer-ip-address: true

Eureka.instance.instance-id: ${spring.cloud.client.ipAddress}: ${server.port}

Spring.cloud.inetutils.preferred-networks Settin

Move the configuration of spring.cloud.inetutils.preferred-networks from the application.yml file to external, the jar command-Dspring.cloud.inetutils.preferred-networks: 192.168.239. Override or set in the environment variable of the system. It is more convenient to use dockerfile or docker compose.

This is the end of the article on "how to configure multiple network cards in SpringCloud Eureka". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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