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HBase, mail # user - connection loss for /hbase


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Geoff Hendrey 2011-06-04, 00:28
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Re: connection loss for /hbase
Cosmin Lehene 2011-06-04, 09:56
Hi Geoff,

The default number of connections in ZK is 10 I believe. You don't need 32K for 100 mappers. But it would help to increase that.
Here's my answer for a related problem http://stackoverflow.com/questions/6153560/hbase-client-connectionloss-for-hbase-error/

I'm not sure how HBase managed ZK works, but I suspect there's a single instance (somebody correct me if I'm wrong).

There's a "zk dump" link on the HBase master web interface where you can see the status of all ZK connections to each node.
You should run a ZK cluster as well on the HBase nodes (3 or 5 nodes, make sure it's not an even number). Here's a set of puppet recipes for Hadoop, HBase, Zookeeper https://github.com/hstack/puppet as well if you want to automate the setup.

Cosmin

On Jun 4, 2011, at 3:28 AM, Geoff Hendrey wrote:

> Hi Folks -
>
>
>
> I am experiencing "ConnectionLoss for /hbase" when I run a mapreduce job
> with around 100 mappers and TableInputFormat. I am running a fully
> distributed cluster, letting hbase manage zookeeper. I am running HBase
> 90.1. Is the solution, per this jira,
> https://issues.apache.org/jira/browse/HBASE-3773 , to increase
> hbase.zookeeper.property.maxClientCnxns to 32k?
>
>
>
> This is the stack trace that I get.
>
>
>
> Caused by: org.apache.hadoop.hbase.ZooKeeperConnectionException:
> org.apache.hadoop.hbase.ZooKeeperConnectionException:
> org.apache.zookeeper.KeeperException$ConnectionLossException:
> KeeperErrorCode = ConnectionLoss for /hbase
>
>        at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementat
> ion.getZooKeeperWatcher(HConnectionManager.java:988)
>
>        at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementat
> ion.setupZookeeperTrackers(HConnectionManager.java:301)
>
>        at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementat
> ion.<init>(HConnectionManager.java:292)
>
>        at
> org.apache.hadoop.hbase.client.HConnectionManager.getConnection(HConnect
> ionManager.java:155)
>
>        at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:167)
>
>        at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:145)
>
>
>
>
>
> -geoff
>

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Buttler, David 2011-06-06, 16:29