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https://issues.apache.org/jira/browse/CASSANDRA-16364?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17308942#comment-17308942
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Paulo Motta commented on CASSANDRA-16364:
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bq. I will point out that simultaneous bootstrap is actually not valid after
CASSANDRA-2434, so I don't think this is technically a regression.
The issue happens with {{auto_bootstrap: false}}. Previously since token
generation was random, the likelihood of token collision existed but was pretty
low. With {{allocate_tokens_for_local_rf}} by default, since token generation
is deterministic the likelihood of collision is higher if all nodes are brought
up simultaneously (such as when instantiating a new DC or bringing up a CCM
cluster). For instance we have nodes A, B and C. Nodes B and C don't see each
other but see node A so they generate the same tokens and collide, only one of
them succeed.
> Simultaneous bootstrap can cause token collision
> ------------------------------------------------
>
> Key: CASSANDRA-16364
> URL: https://issues.apache.org/jira/browse/CASSANDRA-16364
> Project: Cassandra
> Issue Type: Bug
> Components: Cluster/Membership
> Reporter: Paulo Motta
> Priority: Urgent
> Fix For: 4.0.x
>
>
> While raising a 6-node ccm cluster to test 4.0-beta4, 2 nodes chosen the same
> tokens using the default {{allocate_tokens_for_local_rf}}. However they both
> succeeded bootstrap with colliding tokens.
> We were familiar with this issue from CASSANDRA-13701 and CASSANDRA-16079,
> and the workaround to fix this is to avoid parallel bootstrap when using
> {{allocate_tokens_for_local_rf}}.
> However, since this is the default behavior, we should try to detect and
> prevent this situation when possible, since it can break users relying on
> parallel bootstrap behavior.
> I think we could prevent this as following:
> 1. announce intent to bootstrap via gossip (ie. add node on gossip without
> token information)
> 2. wait for gossip to settle for a longer period (ie. ring delay)
> 3. allocate tokens (if multiple bootstrap attempts are detected, tie break
> via node-id)
> 4. broadcast tokens and move on with bootstrap
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