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From Kun Ren <ren.h...@gmail.com>
Subject Re: Eclipse debug HDFS server side code
Date Tue, 19 Apr 2016 18:33:00 GMT
Hi Vinay,

Thanks a lot for your quick reply.

My current configuration is: I run the pseudo-distributed mode in my one
Linux machine.
Yes, I changed the code in eclipse first, and then re-compiled the code,
and then restart HDFS using the new binary, and re-debug,  but still can
not see any output?  When you said "the console of remote process", do you
mean the console of the terminal that I run the command?

If I want to change some code, Could you please explain a little more about
how to debug/run my new modified code? Thanks so much.



On Tue, Apr 19, 2016 at 2:17 PM, Vinayakumar B <vinayakumarb@apache.org>
wrote:

>
> -Vinay
>
> ---------- Forwarded message ----------
> From: Vinayakumar B <vinayakumarb@apache.org>
> Date: Tue, Apr 19, 2016 at 11:47 PM
> Subject: Re: Eclipse debug HDFS server side code
> To: Kun Ren <ren.hdfs@gmail.com>
>
>
> 1. Since you are debugging remote code, you can't change the code
> dynamically during debugging. If you want to change, put the compiled code
> in remote process, and restart, reconnect and debug again.
> 2. All the console messages will be printed on the console of remote
> process, not in eclipse.
> 3. Though you cannot change the code, but you can change/inspect the value
> of value of an variable in 'display' window.
>
> You can explore more related to these.
>
> -Vinay
>
> On Tue, Apr 19, 2016 at 11:42 PM, Kun Ren <ren.hdfs@gmail.com> wrote:
>
>> 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
>> NameNodeRpcServer.java,
>>
>>       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>
>> wrote:
>>
>>> 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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