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From Ipraveen <praveen.j...@tarmin.com>
Subject RE: how to find out name node is running
Date Wed, 02 Apr 2008 09:56:40 GMT

hi 
 i dont understand what u are saying,
and still i am unable to find the namenode status,
how would i find where it is running? and how to i get configuration object
that can have 
namenode refrences.?

 



Jim Kellerman wrote:
> 
> What we do in HBase is the following:
> 
> this.fs = FileSystem.get(conf);
> if (this.fs instanceof DistributedFileSystem) {
>   // Make sure dfs is not in safe mode
>   String message = "Waiting for dfs to exit safe mode...";
>   while (((DistributedFileSystem) fs).setSafeMode(
>     FSConstants.SafeModeAction.SAFEMODE_GET)) {
>     LOG.info(message);
>     try {
>       Thread.sleep(this.threadWakeFrequency);
>     } catch (InterruptedException e) {
>       //continue
>     }
>   }
> }
> 
> In Hadoop 0.16, this will fail if you are running with
> privileges enabled and your application is not running
> as Superuser. However, querying the namenode state does
> not require privileges in Hadoop 0.17
> 
> 
> ---
> Jim Kellerman, Senior Engineer; Powerset
> 
> 
>> -----Original Message-----
>> From: Andy Li [mailto:annndy.lee@gmail.com]
>> Sent: Tuesday, March 25, 2008 11:54 PM
>> To: core-dev@hadoop.apache.org
>> Subject: Re: how to find out name node is running
>>
>> I believe this class is the one you are looking for.
>>
>> org.apache.hadoop.dfs.namenode.metrics.NameNodeStatistics
>>
>> I just went through the API list from the website 0.16.0 and
>> found this one.
>> A blunt guess is that if you can invoke these method and get
>> a response, then you can probably assume the namenode is
>> alive.  But you will need to do some code hacking to figure
>> out how to use it and study it a little bit to understand
>> what is going on underneath to confirm.  Just a reference.
>>
>> -Andy
>>
>> On Tue, Mar 25, 2008 at 11:16 PM, Ipraveen
>> <praveen.jain@tarmin.com> wrote:
>>
>> >
>> > yes you are right Andy , i want to know is there is any
>> hadoop library
>> > api which can trace name node or datnode  ?
>> >
>> >
>> > Andy Li-3 wrote:
>> > >
>> > > That's relying on Java Virtual Machine process status
>> tool, similar
>> > > to
>> > 'ps
>> > > aux|grep java' on a Linux?
>> > >
>> > > I think the question is whether there is any API from
>> Hadoop library
>> > which
>> > > can monitor the namenode
>> > > through a Java API without relying 3rd party utility
>> tool.  Am I right?
>> > >
>> > > -Andy
>> > >
>> > > On Tue, Mar 25, 2008 at 6:26 AM, Zhu Huijun <nautilushj@gmail.com>
>> > wrote:
>> > >
>> > >> Type the command "jps" in your command window. If your
>> name node is
>> > >> running, there will be an output item of "Namenode". Or
>> check the
>> > >> web page at http://localhost:50070 if you did not change the
>> > >> default server host
>> > and
>> > >> port of the web.
>> > >>
>> > >> 2008/3/25, Ipraveen <praveen.jain@tarmin.com>:
>> > >> >
>> > >> >
>> > >> > hi
>> > >> > how would i know whether a name node is runnning or not?
>> > >> > by using hadoop API for java.
>> > >> >
>> > >> > regards
>> > >> > praveen jain
>> > >> > --
>> > >> > View this message in context:
>> > >> >
>> > >>
>> >
>> http://www.nabble.com/how-to-find-out-name-node-is-running-tp16274770p
>> > 16274770.html
>> > >> > Sent from the Hadoop core-dev mailing list archive at
>> Nabble.com.
>> > >> >
>> > >> >
>> > >>
>> > >
>> > >
>> >
>> > --
>> > View this message in context:
>> >
>> http://www.nabble.com/how-to-find-out-name-node-is-running-tp16274770p
>> > 16296276.html Sent from the Hadoop core-dev mailing list archive at
>> > Nabble.com.
>> >
>> >
>>
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>> Date: 3/26/2008 8:52 AM
>>
>>
> 
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> 
> 
> 

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