How to override the ribbon.serverListRefreshInterval default value in Spring Cloud Ribbon?

Question

I wrote a simple Spring Cloud Ribbon application, to call a REST service which was registered in Eureka.

But how to override the ribbon.serverListRefreshInterv

Answer 1

@codependent

After put below configuration in application.yml, it looked the configuration didnt take effect.

Compute-Service:   
  ribbon:  
    ServerListRefreshInterval: 1000

I observed that the instances list has been updated in Ribbon side (through eureka.client.registry-fetch-interval-seconds parameter), however Ribbon still point out a dead instance:

[tbeatExecutor-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_RIBBON-CONSUMER/192.168.1.101:Ribbon-Consumer:3333 - Heartbeat status: 200  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Got delta update with apps hashcode UP_2_  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Added instance 192.168.1.101:Ribbon-Consumer:3333 to the existing apps in region null  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Deleted instance 192.168.1.101:Compute-Service:2222 to the existing apps  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Added instance 192.168.1.101:Compute-Service:1111 to the existing apps in region null  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : The total number of instances fetched by the delta processor : 3  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : The total number of all instances in the client now is 2  
[freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Completed cache refresh task for discovery. All Apps hash code is Local region apps hashcode: UP_2_, is fetching remote regions? false  
[nio-3333-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://Compute-Service/add": Connection refused; nested exception is java.net.ConnectException: Connection refused] with root cause 

192.168.1.101:Compute-Service:1111 was right service instance, while 192.168.1.101:Compute-Service:2222 was dead instance, obviously Ribbon still pointed to the dead instance, which meant Ribbon ServerList cache was not refreshed.

Answer 2

Try with:

myService.ribbon.ServerListRefreshInterval=10000

where myService is the name of your destination microservice.

UPDATE:

After some source code digging I found out that LoadBalancerBuilder calls:

@Deprecated
public ZoneAwareLoadBalancer(IClientConfig clientConfig, IRule rule,
        IPing ping, ServerList<T> serverList, ServerListFilter<T> filter) {
    super(clientConfig, rule, ping, serverList, filter);
}

whose super is:

@Deprecated
public DynamicServerListLoadBalancer(IClientConfig clientConfig, IRule rule, IPing ping, 
        ServerList<T> serverList, ServerListFilter<T> filter) {
    this(
            clientConfig,
            rule,
            ping,
            serverList,
            filter,
            new PollingServerListUpdater()
    );
} 

Notice the PollingServerListUpdater constructors:

private static int LISTOFSERVERS_CACHE_REPEAT_INTERVAL = 30 * 1000; // msecs;

public PollingServerListUpdater() {
    this(LISTOFSERVERS_CACHE_UPDATE_DELAY, LISTOFSERVERS_CACHE_REPEAT_INTERVAL);
}

public PollingServerListUpdater(IClientConfig clientConfig) {
    this(LISTOFSERVERS_CACHE_UPDATE_DELAY, getRefreshIntervalMs(clientConfig));
}

The second one would allow us to override the default refresh interval. However it's the first one that's called, so it ignores de property.

UPDATE 2:

There's an open issue about this: https://github.com/spring-cloud/spring-cloud-netflix/issues/1304