[jira] [Comment Edited] (CASSANDRA-5571) Reject bootstrapping endpoints that are already in the ring with different gossip data

["Brandon Williams (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-5571?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13799542#comment-13799542 ] 

Brandon Williams edited comment on CASSANDRA-5571 at 10/18/13 9:37 PM:
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The problem with this patch is that it checks gossip regardless of whether it's going to bootstrap or not; this means you can't just simply restart an existing node.


was (Author: brandon.williams):
The problem with this patch is that it checks gossip regardless of whether it's going to bootstrap or not; this means you can't just simply restart and existing node.

> Reject bootstrapping endpoints that are already in the ring with different gossip data
> --------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-5571
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5571
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Rick Branson
>            Assignee: Tyler Hobbs
>         Attachments: 5571-2.0-v1.patch
>
>
> The ring can be silently broken by improperly bootstrapping an endpoint that has an existing entry in the gossip table. In the case where a node attempts to bootstrap with the same IP address as an existing ring member, the old token metadata is dropped without warning, resulting in range shifts for the cluster.
> This isn't so bad for non-vnode cases where, in general, tokens are explicitly assigned, and a bootstrap on the same token would result in no range shifts. For vnode cases, the convention is to just let nodes come up by selecting their own tokens, and a bootstrap will override the existing tokens for that endpoint.
> While there are some other issues open for adding an explicit rebootstrap feature for vnode cases, given the changes in operator habits for vnode rings, it seems a bit too easy to make this happen. Even more undesirable is the fact that it's basically silent.
> This is a proposal for checking for this exact case: bootstraps on endpoints with existing ring entries that have different hostIDs and/or tokens should be rejected with an error message describing what happened and how to override the safety check. It looks like the override can be supported using the existing "nodetool removenode -force".
> I can work up a patch for this.



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