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https://issues.apache.org/jira/browse/CASSANDRA-5836?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16383984#comment-16383984
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Robert Coli commented on CASSANDRA-5836:
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I should probably join #cassandra-dev IRC and chat about this there, but I'd
like to refer people to this comment up-ticket :
https://issues.apache.org/jira/browse/CASSANDRA-5836?focusedCommentId=13727032&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13727032
Nobody really seems to understand why it's not safe for a seed node to
bootstrap, because the workaround is to temporarily pretend the node isn't a
seed and to bootstrap it. Usually one doesn't even inform the other nodes that
it temporarily isn't a seed, and nothing unsafe seems to happen.
I feel like clarity here starts with explaining in what cases a Seed node is
actually "Seeding" and what "Seeding" means and does not mean. My understanding
is that the 'seed node' role has a significant initial-topology-discovery
responsibility which I have not seen mentioned in recent discussions. This
dovetails with needing to understand seed node behavior in the "restoring from
snapshot" case, where the topology is known from existing cluster information
and therefore may or may not "need" to be discovered from a seed. Also, as of
my last knowledge of this code, a given node will gossip with a Seed node more
frequently than its other peers, which I believe is "just an optimization of
gossip" but seems notable.
I also recall past dev discussion (with driftx?) suggesting that the "correct"
solution in their view is an external seed provider.
So in summary my understanding of the complete responsibilities of a seed,
independent from whether it's serving as a bootstrap source or bootstrapping
itself :
#) provide other nodes which consider it a seed with initial topology
#) provide "faster" topology updates to nodes which have me listed in their
seed provider
The minimum requirement for a new node joining the cluster seems to be a single
seed node that can inform it of topology in a timely manner. If that's correct
and we imagine that all nodes use a seed provider that always returns at least
one available node that can fulfill that role, the problem (?) of not being
able to bootstrap seed nodes seems to disappear?
> Seed nodes should be able to bootstrap without manual intervention
> ------------------------------------------------------------------
>
> Key: CASSANDRA-5836
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5836
> Project: Cassandra
> Issue Type: Bug
> Reporter: Bill Hathaway
> Priority: Minor
>
> The current logic doesn't allow a seed node to be bootstrapped. If a user
> wants to bootstrap a node configured as a seed (for example to replace a seed
> node via replace_token), they first need to remove the node's own IP from the
> seed list, and then start the bootstrap process. This seems like an
> unnecessary step since a node never uses itself as a seed.
> I think it would be a better experience if the logic was changed to allow a
> seed node to bootstrap without manual intervention when there are other seed
> nodes up in a ring.
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