How to override the ribbon.serverListRefreshInterv

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.serverListRefreshInterval value? The default value is 30 seconds, I'd like to reduce the time interval.

Thanks in advance.

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