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From Mohit Anchlia <mohitanch...@gmail.com>
Subject Re: How to replace a dead *seed* node while keeping quorum
Date Wed, 12 Sep 2012 22:58:14 GMT
How can this be resolved in this case?

On Wed, Sep 12, 2012 at 3:53 PM, Rob Coli <rcoli@palominodb.com> wrote:

> On Tue, Sep 11, 2012 at 4:21 PM, Edward Sargisson
> <edward.sargisson@globalrelay.net> wrote:
> > If the downed node is a seed node then neither of the replace a dead node
> > procedures work (-Dcassandra.replace_token and taking initial_token-1).
> The
> > ring remains split.
> > [...]
> > In other words, if the host name is on the seeds list then it appears
> that
> > the rest of the ring refuses to bootstrap it.
>
> Close, but not exactly...
>
> "./src/java/org/apache/cassandra/service/StorageService.java" line 559 of
> 3090
> "
> if (DatabaseDescriptor.isAutoBootstrap()
>                 &&
> DatabaseDescriptor.getSeeds().contains(FBUtilities.getBroadcastAddress())
>                 && !SystemTable.isBootstrapped())
>             logger_.info("This node will not auto bootstrap because it
> is configured to be a seed node.");
> "
>
> getSeeds asks your seed provider for a list of seeds. If you are using
> the SimpleSeedProvider, this basically turns the list from "seeds" in
> cassandra.yaml on the local node into a list of hosts.
>
> So it isn't that the other nodes have this node in their seed list..
> it's that the node you are replacing has itself in its own seed list,
> and shouldn't. I understand that it can be tricky in conf management
> tools to make seed nodes' seed lists not contain themselves, but I
> believe it is currently necessary in this case.
>
> FWIW, it's unclear to me (and Aaron Morton, whose curiousity was
> apparently equally piqued and is looking into it further..) why
> exactly seed nodes shouldn't bootstrap. It's possible that they only
> shouldn't bootstrap without being in "hibernate" mode, and that the
> code just hasn't been re-written post replace_token/hibernate to say
> that it's ok for seed nodes to bootstrap as long as they hibernate...
>
> =Rob
>
> --
> =Robert Coli
> AIM&GTALK - rcoli@palominodb.com
> YAHOO - rcoli.palominob
> SKYPE - rcoli_palominodb
>

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