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Jon Haddad commented on CASSANDRA-16364: ---------------------------------------- I think we should apply some randomness to the tokens to ensure that even in the case of 1 nodes starting at once, it's still unlikely that they will ever have a conflict. Applying a random() value to the token value between - 2^8 and 2^8 makes this statistically very, very unlikely that we'll ever have a collision while also preserving the balance of token distribution in the ring. In the case of 2 nodes starting at the same time, the operator will have weird token distribution instead of data loss. > Joining nodes simultaneously with auto_bootstrap:false 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: Normal > Fix For: 4.0.x, 4.1.x, 5.0.x, 5.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 -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org