Are there any plans to build redundancy/failover support for the Job
Tracker and Name Node components in Hadoop? Let's take the current
scenario:

1) A data/cpu intensive job is submitted to a Hadoop cluster of 10 machines.
2) Half-way through the job execution, the Job Tracker or Name Node fails.
3) We bring up a new Job Tracker or Name Node manually.

-- Will the individual task trackers / data nodes "reconnect" to the
new masters? Or will the job have to be resubmitted? If we had
failover support, we could setup essentially 3 Job Tracker masters and
3 NameNode masters so that if one dies the other would gracefully take
over and start handling results from the children nodes.

Thanks!

Ryan

Yes, there is a JIRA issue for a redundant JobTracker already.
The NN redundancy scenario is mentioned on the Wiki (look for SecondaryNameNode).

Otis

 --
Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch

----- Original Message ----
> From: Ryan LeCompte <[EMAIL PROTECTED]>
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Sent: Friday, January 9, 2009 3:09:13 PM
> Subject: Job Tracker/Name Node redundancy
>
> Are there any plans to build redundancy/failover support for the Job
> Tracker and Name Node components in Hadoop? Let's take the current
> scenario:
>
> 1) A data/cpu intensive job is submitted to a Hadoop cluster of 10 machines.
> 2) Half-way through the job execution, the Job Tracker or Name Node fails.
> 3) We bring up a new Job Tracker or Name Node manually.
>
> -- Will the individual task trackers / data nodes "reconnect" to the
> new masters? Or will the job have to be resubmitted? If we had
> failover support, we could setup essentially 3 Job Tracker masters and
> 3 NameNode masters so that if one dies the other would gracefully take
> over and start handling results from the children nodes.
>
> Thanks!
>
> Ryan

Hey Ryan,

Some specific JIRA tickets that will help narrow your search:

JT: https://issues.apache.org/jira/browse/HADOOP-4586
NN: https://issues.apache.org/jira/browse/HADOOP-4539

Would love to hear your thoughts there!

Regards,
Jeff

On Fri, Jan 9, 2009 at 12:36 PM, Otis Gospodnetic <
[EMAIL PROTECTED]> wrote:

> Yes, there is a JIRA issue for a redundant JobTracker already.
> The NN redundancy scenario is mentioned on the Wiki (look for
> SecondaryNameNode).
>
> Otis
>
>  --
> Sematext -- http://sematext.com/ -- Lucene - Solr - Nutch
>
>
>
> ----- Original Message ----
> > From: Ryan LeCompte <[EMAIL PROTECTED]>
> > To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> > Sent: Friday, January 9, 2009 3:09:13 PM
> > Subject: Job Tracker/Name Node redundancy
> >
> > Are there any plans to build redundancy/failover support for the Job
> > Tracker and Name Node components in Hadoop? Let's take the current
> > scenario:
> >
> > 1) A data/cpu intensive job is submitted to a Hadoop cluster of 10
> machines.
> > 2) Half-way through the job execution, the Job Tracker or Name Node
> fails.
> > 3) We bring up a new Job Tracker or Name Node manually.
> >
> > -- Will the individual task trackers / data nodes "reconnect" to the
> > new masters? Or will the job have to be resubmitted? If we had
> > failover support, we could setup essentially 3 Job Tracker masters and
> > 3 NameNode masters so that if one dies the other would gracefully take
> > over and start handling results from the children nodes.
> >
> > Thanks!
> >
> > Ryan
>
>

Ryan,
>From the MR (JobTracker) side we have a failover support.
If a large job is submitted and the JobTracker fails midway then you can start the JobTracker on the same host and resume
the job. Look at https://issues.apache.org/jira/browse/HADOOP-3245 for more details. Hope that helps.

Amar
-----Original Message-----
From: Ryan LeCompte [mailto:[EMAIL PROTECTED]]
Sent: Fri 1/9/2009 12:09 PM
To: [EMAIL PROTECTED]
Subject: Job Tracker/Name Node redundancy
 
Are there any plans to build redundancy/failover support for the Job
Tracker and Name Node components in Hadoop? Let's take the current
scenario:

1) A data/cpu intensive job is submitted to a Hadoop cluster of 10 machines.
2) Half-way through the job execution, the Job Tracker or Name Node fails.
3) We bring up a new Job Tracker or Name Node manually.

-- Will the individual task trackers / data nodes "reconnect" to the
new masters? Or will the job have to be resubmitted? If we had
failover support, we could setup essentially 3 Job Tracker masters and
3 NameNode masters so that if one dies the other would gracefully take
over and start handling results from the children nodes.

Thanks!

Ryan