Jiandan Yang  created HDFS-13915:
------------------------------------

             Summary: replace datanode failed because of  
NameNodeRpcServer#getAdditionalDatanode returning excessive datanodeInfo
                 Key: HDFS-13915
                 URL: https://issues.apache.org/jira/browse/HDFS-13915
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: hdfs
         Environment: 

            Reporter: Jiandan Yang 
            Assignee: Jiandan Yang 


Consider following situation:
1. create a file with ALLSSD policy

2. return [SSD,SSD,DISK] due to lack of SSD space

3. client call NameNodeRpcServer#getAdditionalDatanode when recovering write 
pipeline and replacing bad datanode

4. BlockPlacementPolicyDefault#chooseTarget will call 
StoragePolicy#chooseStorageTypes(3, [SSD,DISK], none, false), but 
chooseStorageTypes return [SSD,SSD]

5. do numOfReplicas = requiredStorageTypes.size() and numOfReplicas is set to 2 
and choose additional two datanodes

6. BlockPlacementPolicyDefault#chooseTarget return four datanodes to client

7. DataStreamer#findNewDatanode find nodes.length != original.length + 1  and 
throw IOException, and finally lead to write failed

client warn logs is:
 \{code:java}

WARN [DataStreamer for file 
/home/yarn/opensearch/in/data/120141286/0_65535/table/ucs_process/MANIFEST-093545
 block BP-1742758844-11.138.8.184-1483707043031:blk_7086344902_6012765313] 
org.apache.hadoop.hdfs.DFSClient: DataStreamer Exception

java.io.IOException: Failed to replace a bad datanode on the existing pipeline 
due to no more good datanodes being available to try. (Nodes: 
current=[DatanodeInfoWithStorage[11.138.5.4:50010,DS-04826cfc-1885-4213-a58b-8606845c5c42,SSD],
 
DatanodeInfoWithStorage[11.138.5.9:50010,DS-f6d8eb8b-2550-474b-a692-c991d7a6f6b3,SSD],
 
DatanodeInfoWithStorage[11.138.5.153:50010,DS-f5d77ca0-6fe3-4523-8ca8-5af975f845b6,SSD],
 
DatanodeInfoWithStorage[11.138.9.156:50010,DS-0d15ea12-1bad-4444-84f7-1a4917a1e194,DISK]],
 
original=[DatanodeInfoWithStorage[11.138.5.4:50010,DS-04826cfc-1885-4213-a58b-8606845c5c42,SSD],
 
DatanodeInfoWithStorage[11.138.9.156:50010,DS-0d15ea12-1bad-4444-84f7-1a4917a1e194,DISK]]).
 The current failed datanode replacement policy is DEFAULT, and a client may 
configure this via 'dfs.client.block.write.replace-datanode-on-failure.policy' 
in its configuration.

{code}



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