[HDFS-8582] Support getting a list of reconfigurable config properties and do not generate spurious reconfig warnings

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.7.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: datanode, hdfs-client
• Target Version/s: 2.8.0
• Release Note: Add a new option "properties" to the "dfsadmin -reconfig" command to get a list of reconfigurable properties.
• Assignee: Lei (Eddy) Xu Assign to me
• Reporter: Lei (Eddy) Xu
• Created: 11/Jun/15 21:37
• Updated: 30/Aug/16 01:32
• Resolved: 20/Jun/15 02:15

Description

When running a DN reconfig to hotswap some drives, it spits out this output:

$ hdfs dfsadmin -reconfig datanode localhost:9023 status
15/06/09 14:58:10 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Reconfiguring status for DataNode[localhost:9023]: started at Tue Jun 09 14:57:37 PDT 2015 and finished at Tue Jun 09 14:57:56 PDT 2015.
FAILED: Change property rpc.engine.org.apache.hadoop.hdfs.protocolPB.ClientDatanodeProtocolPB
        From: "org.apache.hadoop.ipc.ProtobufRpcEngine"
        To: ""
        Error: Property rpc.engine.org.apache.hadoop.hdfs.protocolPB.ClientDatanodeProtocolPB is not reconfigurable.
FAILED: Change property mapreduce.client.genericoptionsparser.used
        From: "true"
        To: ""
        Error: Property mapreduce.client.genericoptionsparser.used is not reconfigurable.
FAILED: Change property rpc.engine.org.apache.hadoop.ipc.ProtocolMetaInfoPB
        From: "org.apache.hadoop.ipc.ProtobufRpcEngine"
        To: ""
        Error: Property rpc.engine.org.apache.hadoop.ipc.ProtocolMetaInfoPB is not reconfigurable.
SUCCESS: Change property dfs.datanode.data.dir
        From: "file:///data/1/user/dfs"
        To: "file:///data/1/user/dfs,file:///data/2/user/dfs"
FAILED: Change property dfs.datanode.startup
        From: "REGULAR"
        To: ""
        Error: Property dfs.datanode.startup is not reconfigurable.
FAILED: Change property rpc.engine.org.apache.hadoop.hdfs.protocolPB.InterDatanodeProtocolPB
        From: "org.apache.hadoop.ipc.ProtobufRpcEngine"
        To: ""
        Error: Property rpc.engine.org.apache.hadoop.hdfs.protocolPB.InterDatanodeProtocolPB is not reconfigurable.
FAILED: Change property rpc.engine.org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolPB
        From: "org.apache.hadoop.ipc.ProtobufRpcEngine"
        To: ""
        Error: Property rpc.engine.org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolPB is not reconfigurable.
FAILED: Change property rpc.engine.org.apache.hadoop.tracing.TraceAdminProtocolPB
        From: "org.apache.hadoop.ipc.ProtobufRpcEngine"
        To: ""
        Error: Property rpc.engine.org.apache.hadoop.tracing.TraceAdminProtocolPB is not reconfigurable.

These failed messages are spurious and should not be shown.