Minor Description
I set `dfs.nameservices` with the value of one name service (let’s say `ns1` for simplicity) and forgot to set `dfs.namenode.rpc-address.ns1`.
Then I got an error message:
[ERROR] testNonFederation(org.apache.hadoop.hdfs.tools.TestGetConf) Time elapsed: 0.195 s <<< ERROR!
java.io.IOException: Incorrect configuration: namenode address dfs.namenode.servicerpc-address or dfs.namenode.rpc-address is not configured.
at org.apache.hadoop.hdfs.DFSUtil.getNNServiceRpcAddressesForCluster(DFSUtil.java:629)
at org.apache.hadoop.hdfs.tools.TestGetConf.getAddressListFromConf(TestGetConf.java:132)
at org.apache.hadoop.hdfs.tools.TestGetConf.verifyAddresses(TestGetConf.java:234)
at org.apache.hadoop.hdfs.tools.TestGetConf.testNonFederation(TestGetConf.java:308)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:298)
at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:292)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.lang.Thread.run(Thread.java:748)
The error message above told me that `dfs.namenode.rpc-address` or `dfs.namenode.servicerpc-address` should be set.
However, the actual reason for the error is that `dfs.namenode.rpc-address.ns1` or `dfs.namenode.servicerpc-address.ns1` is not set.
How to improve
I wrote a patch to improve the error message. Here is the current error message:
[ERROR] testNonFederation(org.apache.hadoop.hdfs.tools.TestGetConf) Time elapsed: 0.195 s <<< ERROR! java.io.IOException: Incorrect configuration: namenode address dfs.namenode.servicerpc-address[.$NAMESERVICE] or dfs.namenode.rpc-address[.$NAMESERVICE] is not configured.
Then the users can immediately know that they should set `dfs.namenode.rpc-address.ns1` or `dfs.namenode.servicerpc-address.ns1` according to the error message.