hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Mingliang Liu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-10986) DFSAdmin should log detailed error message if any
Date Tue, 11 Oct 2016 21:30:20 GMT

    [ https://issues.apache.org/jira/browse/HDFS-10986?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15566678#comment-15566678
] 

Mingliang Liu commented on HDFS-10986:
--------------------------------------

Thanks for the review, [~xiaobingo].

{quote}
You might want to log it as warning or error msgs.
{code}234	      LOG.info("stderr: " + err);{code}
{quote}
This is for test assistance readability. The stderr is expected instead of a real test error.
In v3 patch, I merged the stdout/stderr with the assertion message; if the test fails, the
failing message will have the detailed stderr/stdout message:
{code}
      assertTrue("Unexpected " + command + " stdout: " + out, outs.isEmpty());
      assertTrue("Unexpected " + command + " stderr: " + err,
          err.toString().contains("Exception"));
{code}

{quote}
java.lang.Exception: test timed out after 60000 milliseconds
{quote}
The reason was that the previous test in [HDFS-10972] is using 128.0.0.1 which is an external
IP address. We can not depend on such resource and assume the 1234 port there is not responding.
In v3 patch, I keep the connection failure case where we use the Xfer port instead of IPC
port on localhost. The DFSAdmin will get "Datanode unreachable. java.io.EOFException" immediately
and the test can pass locally.

> DFSAdmin should log detailed error message if any
> -------------------------------------------------
>
>                 Key: HDFS-10986
>                 URL: https://issues.apache.org/jira/browse/HDFS-10986
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: tools
>            Reporter: Mingliang Liu
>            Assignee: Mingliang Liu
>         Attachments: HDFS-10986-branch-2.8.002.patch, HDFS-10986-branch-2.8.003.patch,
HDFS-10986.000.patch, HDFS-10986.001.patch, HDFS-10986.002.patch, HDFS-10986.003.patch
>
>
> There are some subcommands in {{DFSAdmin}} that swallow IOException and give very limited
error message, if any, to the stderr.
> {code}
> $ hdfs dfsadmin -getBalancerBandwidth 127.0.0.1:9866
> Datanode unreachable.
> $ hdfs dfsadmin -getDatanodeInfo localhost:9866
> Datanode unreachable.
> $ hdfs dfsadmin -evictWriters 127.0.0.1:9866
> $ echo $?
> -1
> {code}
> User is not able to get the exception stack even the LOG level is DEBUG. This is not
very user friendly. Fortunately, if the port number is not accessible (say 9999), users can
infer the detailed error message by IPC logs:
> {code}
> $ hdfs dfsadmin -getBalancerBandwidth 127.0.0.1:9999
> 2016-10-07 18:01:35,115 WARN util.NativeCodeLoader: Unable to load native-hadoop library
for your platform... using builtin-java classes where applicable
> 2016-10-07 18:01:36,335 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9999.
Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10,
sleepTime=1000 MILLISECONDS)
> .....
> 2016-10-07 18:01:45,361 INFO ipc.Client: Retrying connect to server: localhost/127.0.0.1:9999.
Already tried 9 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10,
sleepTime=1000 MILLISECONDS)
> 2016-10-07 18:01:45,362 WARN ipc.Client: Failed to connect to server: localhost/127.0.0.1:9999:
retries get failed due to exceeded maximum allowed retries number: 10
> java.net.ConnectException: Connection refused
> 	at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
> 	at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
>         ...
> 	at org.apache.hadoop.hdfs.tools.DFSAdmin.run(DFSAdmin.java:2073)
> 	at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76)
> 	at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:90)
> 	at org.apache.hadoop.hdfs.tools.DFSAdmin.main(DFSAdmin.java:2225)
> Datanode unreachable.
> {code}
> We should fix this by providing detailed error message. Actually, the {{DFSAdmin#run}}
already handles exception carefully, including:
> # set the exit ret value to -1
> # print the error message
> # log the exception stack trace (in DEBUG level)
> All we need to do is to not swallow exceptions without good reason.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-help@hadoop.apache.org


Mime
View raw message