What does this error mean?

This error indicates a CountdownLatch thread task was interrupted during a migration process.

Why does this error occur?

This would occur if the MigrationTask being iterated over was interrupted. This specific message occurs in the catch block of the waitUntilReadyForBootstrap method. The catch block specifically catches an InterruptedException, which in turn causes the current thread to interrupt itself.

How do you fix this error?

If you encounter this error, please file a ticket with DataStax Support.