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From Vivek Shrivastava <vshrivast...@Shopzilla.com>
Subject RE: Netstat Shows Port 8020 Doesn't Seem to Listen
Date Mon, 09 Jan 2012 23:03:23 GMT
One of the option to troubleshoot is to run open your url in the lynx, on the command line
it will be not be affected by any firewall and will be a local access...

Regards,

Vivek

-----Original Message-----
From: Eli Finkelshteyn [mailto:iefinkel@gmail.com] 
Sent: Monday, January 09, 2012 2:39 PM
To: common-user@hadoop.apache.org
Subject: Re: Netstat Shows Port 8020 Doesn't Seem to Listen

Good call! netstat -anl gives me:
tcp        0      0 ::ffff:127.0.0.1:8020       
:::*                        LISTEN

Now it just looks like nothing is running on 8021. And now I'm really 
confused about why I get no communication over 8020 from the datanode.

Just to reiterate, this definitely is not the firewall, running iptables 
-nvL gives:

...
     0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            
0.0.0.0/0           state NEW tcp dpt:50070
     1    64 ACCEPT     tcp  --  *      *       0.0.0.0/0            
0.0.0.0/0           state NEW tcp dpt:50030
     0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            
0.0.0.0/0           state NEW tcp dpt:8021
     1    64 ACCEPT     tcp  --  *      *       0.0.0.0/0            
0.0.0.0/0           state NEW tcp dpt:8020
...

On 1/9/12 5:08 PM, alo.alt wrote:
> What happen when you try a "telnet localhost 8020"?
> netstat -anl would also useful.
>
> best,
>   Alex
>
> --
> Alexander Lorenz
> http://mapredit.blogspot.com
>
> On Jan 9, 2012, at 2:02 PM, Eli Finkelshteyn wrote:
>
>> A bit more info:
>>
>> When I start up only the namenode by itself, I'm not seeing any errors, but what
I am seeing that's really odd is:
>>
>>    2012-01-09 16:48:45,530 INFO org.apache.hadoop.ipc.Server: Starting
>>    Socket Reader #1 for port 8020
>>    2012-01-09 16:48:45,531 INFO
>>    org.apache.hadoop.ipc.metrics.RpcMetrics: Initializing RPC Metrics
>>    with hostName=NameNode, port=8020
>>    2012-01-09 16:48:45,532 INFO
>>    org.apache.hadoop.ipc.metrics.RpcDetailedMetrics: Initializing RPC
>>    Metrics with hostName=NameNode, port=8020
>>    2012-01-09 16:48:45,541 INFO
>>    org.apache.hadoop.hdfs.server.namenode.NameNode: Namenode up at:
>>    localhost.localdomain/127.0.0.1:8020
>>
>> That's despite the fact that doing netstat -a | grep 8020 still returns nothing.
 To me, that makes absolutely no sense. I feel like I should be getting an error telling me
Namenode did not in fact go up on 8020, but I'm not getting that at all.
>>
>> Eli
>>
>> On 1/9/12 3:22 PM, Idris Ali wrote:
>>> Hi,
>>>
>>> Looks like problem in starting DFS and MR, can you run 'jps' and see if NN,
>>> DN, SNN, JT and TT are running,
>>>
>>> also make sure for pseudo-distributed mode, the following entries are
>>> present:
>>>
>>> 1. In core-site.xml
>>>   <property>
>>>      <name>fs.default.name</name>
>>>      <value>hdfs://localhost:8020</value>
>>>    </property>
>>>
>>>    <property>
>>>       <name>hadoop.tmp.dir</name>
>>>       <value><SOME TMP dir with Read/Write acces not system temp></value>
>>>    </property>
>>>    <property>
>>>
>>> 2.  In hdfs-site.xml
>>> <property>
>>>      <name>dfs.replication</name>
>>>      <value>1</value>
>>>    </property>
>>>    <property>
>>>       <name>dfs.permissions</name>
>>>       <value>false</value>
>>>    </property>
>>>    <property>
>>>       <!-- specify this so that running 'hadoop namenode -format' formats
>>> the right dir -->
>>>       <name>dfs.name.dir</name>
>>>       <value>Local dir with Read/Write access</value>
>>>    </property>
>>>
>>> 3. In mapred-stie.xml
>>>    <property>
>>>      <name>mapred.job.tracker</name>
>>>      <value>localhost:8021</value>
>>>    </property>
>>>
>>> Thanks,
>>> -Idris
>>>
>>> On Tue, Jan 10, 2012 at 1:07 AM, Eli Finkelshteyn<iefinkel@gmail.com>wrote:
>>>
>>>> Positive. Like I said before, netstat -a | grep 8020 gives me nothing.
>>>> Even if the firewall was the problem, that should still give me output that
>>>> the port is listening, but I'd just be unable to hit it from an outside box
>>>> (I tested this by blocking port 50070, at which point it still showed up
in
>>>> netstat -a, but was inaccessible through http from a remote machine). This
>>>> problem is something else.
>>>>
>>>>
>>>> On 1/9/12 2:31 PM, zGreenfelder wrote:
>>>>
>>>>> On Mon, Jan 9, 2012 at 1:58 PM, Eli Finkelshteyn<iefinkel@gmail.**com<iefinkel@gmail.com>>
>>>>>   wrote:
>>>>>
>>>>>> More info:
>>>>>>
>>>>>> In the DataNode log, I'm also seeing:
>>>>>>
>>>>>> 2012-01-09 13:06:27,751 INFO org.apache.hadoop.ipc.Client: Retrying
>>>>>> connect
>>>>>> to server: localhost/127.0.0.1:8020. Already tried 9 time(s).
>>>>>>
>>>>>> Why would things just not load on port 8020? I feel like all the
errors
>>>>>> I'm
>>>>>> seeing are caused by this, but I can't see any errors about why this
>>>>>> occurred in the first place.
>>>>>>
>>>>>>   are you sure there isn't a firewall in place blocking port 8020?
>>>>> e.g. iptables on the local machines?   if you do
>>>>> telnet localhost 8020
>>>>> do you make a connection? if you use lsof and/or netstat can you see
>>>>> the port open?
>>>>> if you have root access you can try turning off the firewall with
>>>>> iptables -F to see if things work without firewall rules.
>>>>>



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