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From Michael Segel <michael_se...@hotmail.com>
Subject Re: Recovering the namenode from failure
Date Tue, 21 May 2013 16:33:54 GMT
I think what he's missing is to change the configurations to point to the new name node. 

It sounds like the new NN has a different IP address from the old NN so the DNs don't know
who to report to... 

On May 21, 2013, at 11:23 AM, Todd Lipcon <todd@cloudera.com> wrote:

> Hi David,
> 
> You shouldn't need to do anything to get your DNs to report in -- as best they can tell,
it's the same NN. Do you see any error messages in the DN logs?
> 
> -Todd
> 
> On Tue, May 21, 2013 at 12:30 AM, David Parks <davidparks21@yahoo.com> wrote:
> I’m on CDH4, and trying to recover both the namenode and cloudera manager VMs from
HDFS after losing the namenode.
> 
>  
> 
> All of our backup VMs are on HDFS, so for the moment I just want to hack something together,
copy the backup VMs off HDFS and get on with properly reconfiguring via CDH Manger.
> 
>  
> 
> So I’ve installed a plain ‘ol namenode on one of my cluster nodes and started it
with –importCheckpoint (with the data from the secondary NN), this seems to have worked,
I have a namenode web UI up which expects to find 32178 blocks.
> 
>  
> 
> But my plain namenode (on the same hostname and IP as the old namenode) says that there
are no datanodes in the cluster.
> 
>  
> 
> What do I need in order to configure the datanodes to report their blocks into this new
namenode (same IP & hostname)?
> 
>  
> 
> Thanks,
> 
> David
> 
>  
> 
> 
> 
> 
> -- 
> Todd Lipcon
> Software Engineer, Cloudera


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