这个是Hadoop内部读取配置信息时 使用hashtable 产生了 并发修改错误 ；这个报错是jira里的，自己的找不到了

    1. 2018-03-22 04:57:39,289 INFO  resourcemanager.ResourceTrackerService (ResourceTrackerService.java:nodeHeartbeat(497)) - Node not found resyncing ctr-e138-1518143905142-129550-01-000036.hwx.site:25454
    2. 2018-03-22 04:57:39,294 INFO  service.AbstractService (AbstractService.java:noteFailure(272)) - Service ResourceManager failed in state STARTED; cause: java.util.ConcurrentModificationException
    3. java.util.ConcurrentModificationException
    4.         at java.util.Hashtable$Enumerator.next(Hashtable.java:1378)
    5.         at org.apache.hadoop.conf.Configuration.iterator(Configuration.java:2564)
    6.         at org.apache.hadoop.conf.Configuration.getPropsWithPrefix(Configuration.java:2583)
    7.         at org.apache.hadoop.yarn.webapp.WebApps$Builder.getConfigParameters(WebApps.java:386)
    8.         at org.apache.hadoop.yarn.webapp.WebApps$Builder.build(WebApps.java:334)
    9.         at org.apache.hadoop.yarn.webapp.WebApps$Builder.start(WebApps.java:395)
    10.         at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.startWepApp(ResourceManager.java:1049)
    11.         at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.serviceStart(ResourceManager.java:1152)
    12.         at org.apache.hadoop.service.AbstractService.start(AbstractService.java:193)
    13.         at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.main(ResourceManager.java:1293)
    14. 2018-03-22 04:57:39,296 INFO  ipc.Server (Server.java:stop(2752)) - Stopping server on 8050
    15. 2018-03-22 04:57:39,300 INFO  ipc.Server (Server.java:run(932)) - Stopping IPC Server listener on 8050
    16. 2018-03-22 04:57:39,301 INFO  ipc.Server (Server.java:run(1069)) - Stopping IPC Server Responder

    在使用腾讯云emr的时候遇到，升级emr内的Hadoop版本得以解决；

    1.   /**
    2.    * Get an {@link Iterator} to go through the list of <code>String</code> 
    3.    * key-value pairs in the configuration.
    4.    * 
    5.    * @return an iterator over the entries.
    6.    */
    7.   @Override
    8.   public Iterator<Map.Entry<String, String>> iterator() {
    9.     // Get a copy of just the string to string pairs. After the old object
    10.     // methods that allow non-strings to be put into configurations are removed,
    11.     // we could replace properties with a Map<String,String> and get rid of this
    12.     // code.
    13.     Map<String,String> result = new HashMap<String,String>();
    14.     for(Map.Entry<Object,Object> item: getProps().entrySet()) {
    15.       if (item.getKey() instanceof String &&
    16.           item.getValue() instanceof String) {
    17.           result.put((String) item.getKey(), (String) item.getValue());
    18.       }
    19.     }
    20.     return result.entrySet().iterator();
    21.   }

    1、Hadoop报错ConcurrentModificationException - 图1

    参考：YARN-8109,HADOOP-13500