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From "alo.alt" <wget.n...@googlemail.com>
Subject Re: Netstat Shows Port 8020 Doesn't Seem to Listen
Date Mon, 09 Jan 2012 22:43:38 GMT
Firewall online?
and be sure that in /etc/hosts ONLY 127.0.0.1 is linked to localhost. Nothing like YOURHOSTNAME.YOURDOMAIN
(Redhat kudzu bug)

- Alex 

--
Alexander Lorenz
http://mapredit.blogspot.com

On Jan 9, 2012, at 2:39 PM, Eli Finkelshteyn wrote:

> 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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