From the logs it seems the consumer 562b6738's registry node in Zookeeper
has lost:

NoNode for

As Joel suggested for now you may just stop all your consumers and restart,
to debug you may need to investigate into zookeeper's log checking is there
any session expiration or close socket events happened which cause ZK to
delete the registry node.

Which Kafka version are you using?

On Fri, Jan 10, 2014 at 3:36 PM, Joel Koshy <[EMAIL PROTECTED]> wrote:
NEW: Monitor These Apps!
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