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From Eli Finkelshteyn <iefin...@gmail.com>
Subject Re: Netstat Shows Port 8020 Doesn't Seem to Listen
Date Mon, 09 Jan 2012 22:39:22 GMT
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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