In the NamenodeBeanMetrics the router will invokes 'getDataNodeReport' periodically. And we can set the dfs.federation.router.dn-report.time-out and dfs.federation.router.dn-report.cache-expire to avoid time out. But when we start the router, the FederationMetrics will also invoke the method to get node usage. If time out error happened, we cannot adjust the parameter time_out. And the time_out in the FederationMetrics and NamenodeBeanMetrics should be the same.