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From Kun Ren <ren.h...@gmail.com>
Subject Re: Eclipse debug HDFS server side code
Date Tue, 19 Apr 2016 18:12:38 GMT
Hi Vinay,

Thanks a lot, it works:)

I have another question:
1. When I add the following lines into the public boolean mkdirs(String
src, FsPermission masked, boolean createParent)  in the

      LOG.warn("NameNodeRpcServer.java:mkdirs, log level=warn");
      System.out.println("In NameNodeRpcServer.java:mkdirs, before do
actual work");

But I can not see any output either from my terminal or Eclipse console
when I step-by-step debug this function, do you know why?

2.  When I debug the client side code, for example FsShell, the default log
level is INFO, I changed the level to DEBUG using the
http://localhost:50070/logLevel, however, it still can not print out
LOG.debug(), but I can see LOG.info(),  I don't know why it can not print
out debug information even I set the log level to DEBUG.

Thanks a lot for your help,

On Tue, Apr 19, 2016 at 12:21 PM, Vinayakumar B <vinayakumarb@apache.org>

> Hi Kun Ren,
> You can follow the below steps.
> 1. configure HADOOP_NAMENODE_OPTS="-Xdebug
> -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=3988" in
> hadoop-env.sh
> 2. Start Namenode
> 3. Now Namenode will start debug port in 3988.
> 4. Configure Remote debug application to connect to <namenode_host>:3988
> in eclipse
> 5. Now add a breakpoint in NameNodeRpcServer.java's any method you want to
> debug. NameNodeRpcServer.java is the gateway between NameNode and IPC
> Server Layer.
> 6. Now you can do step-by-step execution to observe the detailed
> executions.
> Happy Debugging ;)
> -Vinay
> On Tue, Apr 19, 2016 at 8:46 PM, Kun Ren <ren.hdfs@gmail.com> wrote:
>> Hi All,
>> Currently I used eclipse to compile/debug the source code, and I
>> configured the "remote Java application" to debug the source code in
>> eclipse, for example, I can debug the  client side code when I run the
>> command "./bin/hdfs dfs -mkdir test", it goes through "FsShell--->
>> DistributedFileSystem---->DFSClient ....->send request to the server side.
>> Then it finish debugging, but I can not see how the server side handle the
>> request.
>> However, I want to debug and see how the server side(HDFS) handle the
>> request? Do you know how I can do this?  Thanks so much. Also when I try to
>> add some debug information(such as print out something), but I can not see
>> anything printed out in eclipse, I don't know why. Thanks again.
>> Best,
>> Kun

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