datanode HA无法启动

首先，使用start-dfs.sh启动服务之后，在手动启动其它服务器的datanode报错如下
2020-04-15 13:52:20,446 FATAL org.apache.hadoop.hdfs.server.datanode.DataNode: Initialization failed for Block pool <registering> (Datanode Uuid unassigned) service to hadoop102/xxx.xxx.xxx.xxx:8020. Exiting.
java.io.IOException: All specified directories are failed to load.
        at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:478)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.initStorage(DataNode.java:1358)
        at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:1323)
        at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:317)
        at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:223)
        at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:802)
        at java.lang.Thread.run(Thread.java:745)
2020-04-15 13:52:20,446 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Ending block pool service for: Block pool <registering> (Datanode Uuid unassigned) service to hadoop102/xxx.xxx.xxx.xxx:8020
2020-04-15 13:52:20,449 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Removed Block pool <registering> (Datanode Uuid unassigned)
2020-04-15 13:52:22,450 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Exiting Datanode
2020-04-15 13:52:22,451 INFO org.apache.hadoop.util.ExitUtil: Exiting with status 0
2020-04-15 13:52:22,462 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: SHUTDOWN_MSG:

报错提示是uuid未指定，没有查到问题

网上找到下面的连接：https://blog.youkuaiyun.com/ZT7524/article/details/93092928

通过检查发现是由于多次执行namenode的初始化导致datanode的集群id不一致

检查配置如下：

namenode VERSION配置信息
#Wed Apr 15 12:56:09 CST 2020
namespaceID=1868237636
clusterID=CID-26bf7250-26c3-41fd-8a37-2b40bd18cd38
cTime=0
storageType=NAME_NODE
blockpoolID=BP-1991139273-192.168.10.101-1586926569194
layoutVersion=-63

datanode VERSION配置信息
#Wed Apr 15 12:59:49 CST 2020
storageID=DS-8e5ec251-8d88-48ca-8709-54581e1bd393
clusterID=CID-f2b59946-1a1d-48a6-9074-4bc01271d777
cTime=0
datanodeUuid=a1c4f299-ef64-4e2f-891d-5a90e39aba06
storageType=DATA_NODE
layoutVersion=-56

更新datanode的集群id之后就可以正常启动了