You can add a Retryer in the FeignClientConfig

@Configuration
public class FeignClientConfig {

    @Bean
    public Retryer retryer() {
        return new Custom();
    }

}

class Custom implements Retryer {

    private final int maxAttempts;
    private final long backoff;
    int attempt;

    public Custom() {
        this(2000, 3);
    }

    public Custom(long backoff, int maxAttempts) {
        this.backoff = backoff;
        this.maxAttempts = maxAttempts;
        this.attempt = 1;
    }

    public void continueOrPropagate(RetryableException e) {
        if (attempt++ >= maxAttempts) {
            throw e;
        }

        try {
            Thread.sleep(backoff);
        } catch (InterruptedException ignored) {
            Thread.currentThread().interrupt();
        }
    }

    @Override
    public Retryer clone() {
        return new Custom(backoff, maxAttempts);
    }
}

Updated with sample Retryer example config based on the Retryer.Default.

Feign has a build in Retryer however you can not configure the Retryer via application.yml. I guess the Spring Boot Team assumed that people would use the deprecated Hystrix project for this matter.

Instead of configuring Feign by config you could write a bit of code: https://cloud.spring.io/spring-cloud-openfeign/reference/html/index.html#creating-feign-clients-manually

In addition you have to map the corresponding status code to RetryableException using a custom ErrorDecoder.

public class CustomErrorDecoder implements ErrorDecoder {
  private final ErrorDecoder errorDecoder = new Default();

  @Override
  public Exception decode(String methodKey, Response response) {
    Exception exception = defaultErrorDecoder.decode(s, response);

    if(exception instanceof RetryableException){
      return exception;
    }

    if(response.status() == 499){
      return new RetryableException("499 blub", response.request().httpMethod(), null );
    }
    return exception;
  }
}

public class Example {
  public static void main(String[] args) {
    MyApi myApi = Feign.builder()
                 .errorDecoder(new CustomErrorDecoder())
                 .target(MyApi.class, "https://api.hostname.com");
  }
}