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From jean paul <researche...@gmail.com>
Subject Re: Question nodetool status
Date Thu, 11 Aug 2016 15:02:15 GMT
Hi, thanks a lot for answer :)

Gossip is a peer-to-peer communication protocol in which nodes periodically
exchange state information about themselves and about other nodes they know
about.

unreachableNodes = probe.getUnreachableNodes();   --->  i.e if node don't
publish heartbeats on x seconds (using gossip protocol), it's therefore
marked 'DN: down' ?


That's it?





2016-08-11 13:51 GMT+01:00 Romain Hardouin <romainh_ml@yahoo.fr>:

> Hi Jean Paul,
>
> Yes, the gossiper is used. Example with down nodes:
> 1. The status command retrieve unreachable nodes from a NodeProbe
> instance: https://github.com/apache/cassandra/blob/trunk/
> src/java/org/apache/cassandra/tools/nodetool/Status.java#L64
> 2. The NodeProbe list comes from a StorageService proxy:
> https://github.com/apache/cassandra/blob/trunk/src/java/
> org/apache/cassandra/tools/NodeProbe.java#L438
> 3. The proxy calls the Gossiper singleton: https://github.com/
> apache/cassandra/blob/trunk/src/java/org/apache/cassandra/
> service/StorageService.java#L2681
>
> Best,
>
> Romain
>
> Le Jeudi 11 août 2016 14h16, jean paul <researcherfr@gmail.com> a écrit :
>
>
> Hi all,
>
>
>
> *$nodetool status*Datacenter: datacenter1
> =======================
> Status=Up/Down
> |/ State=Normal/Leaving/Joining/ Moving
> --  Address    Load       Tokens  Owns (effective)  Host
> ID                                Rack
>
>
> *UN  127.0.0.1  83.05 KB   256     100.0%
> 460ddcd9-1ee8-48b8-a618- c076056aad07  rack1*
> *The nodetool command* shows the status of the node (UN=up, DN=down):
>
> Please i'd like to know how this command works and is it based on gossip
> protocol or not ?
>
> Thank you so much for explanations.
> Best regards.
>
>
>
>
>

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