[MAPREDUCE-4093] Improve RM WebApp start up when proxy address is not set

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha, 3.0.0-alpha1
• Fix Version/s: 2.0.0-alpha
• Component/s: mrv2
• Assignee: Devaraj Kavali
• Reporter: Devaraj Kavali
• Created: 31/Mar/12 16:28
• Updated: 12/May/16 18:24
• Resolved: 19/Apr/12 19:45

Description

ResourceManager.java

  protected void startWepApp() {
    Builder<ApplicationMasterService> builder = 
      WebApps.$for("cluster", ApplicationMasterService.class, masterService, "ws").at(
          this.conf.get(YarnConfiguration.RM_WEBAPP_ADDRESS,
          YarnConfiguration.DEFAULT_RM_WEBAPP_ADDRESS)); 
    if(YarnConfiguration.getRMWebAppHostAndPort(conf).
        equals(YarnConfiguration.getProxyHostAndPort(conf))) {
      AppReportFetcher fetcher = new AppReportFetcher(conf, getClientRMService());
      builder.withServlet(ProxyUriUtils.PROXY_SERVLET_NAME, 
          ProxyUriUtils.PROXY_PATH_SPEC, WebAppProxyServlet.class);
      builder.withAttribute(WebAppProxy.FETCHER_ATTRIBUTE, fetcher);
      String proxy = YarnConfiguration.getProxyHostAndPort(conf);
      String[] proxyParts = proxy.split(":");
      builder.withAttribute(WebAppProxy.PROXY_HOST_ATTRIBUTE, proxyParts[0]);

    }
    webApp = builder.start(new RMWebApp(this));
  }

In the above code, YarnConfiguration.getProxyHostAndPort(conf) is invoking twice. getProxyHostAndPort() internally invokes getRMWebAppHostAndPort() which resolves RM web app address when proxy address is not set.