Heads up: restarting a node with autobootstrap=true after nodetool move will re-bootstrap the node in 0.7.0-0.7.4

[Jonathan Ellis <jb...@gmail.com>]

Peter Schuller reported an important bug in
https://issues.apache.org/jira/browse/CASSANDRA-2435:

"On one of our clusters with 5 nodes, we did some moves. All looked
well; the moves completed. For unrelated reasons, we wanted to restart
nodes after they had been moved. When we did, three of the 5,
specifically those 3 that were NOT seed nodes, initiated a bootstrap
procedure! The logs indicated the automatic token selection, and they
joined the ring under a new automatically selected token."

We're reviewing a fix now for 0.7.5 (this does not affect 0.6
releases); in the meantime, you should make sure to re-set
autobootstrap=false before running any move commands.

Note that this will not cause data loss unless you run cleanup after
the move; the fix is to run another move command, back to the old
token.

-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

Re: Heads up: restarting a node with autobootstrap=true after nodetool move will re-bootstrap the node in 0.7.0-0.7.4

[Peter Schuller <pe...@infidyne.com>]

> What is de-seeding and why would it cause this problem? Relation of seeding
> and auto_bootstrap always confuses me. If and when you have time can you
> please explain it to me.

I was ad-hoc inventing the term 'de-seeding' to mean reconfiguring all
others nodes to not use the node as a seed. And no, it was unrelated
to the problem as I also stated in the ticket was probably the case, I
just wanted to mention it for completeness in the JIRA ticket just in
case there was some interaction there (not having found the bug). It
had nothing to do with the bug.

(I mentioned earlier in the ticket about seed nodes not
re-bootstrapping, but that's because seeds are special-cased in the
start-up process to never initiate bootstrapping and is also unrelated
really to the bug.)

-- 
/ Peter Schuller

Re: Heads up: restarting a node with autobootstrap=true after nodetool move will re-bootstrap the node in 0.7.0-0.7.4

[mcasandra <mo...@gmail.com>]

Thanks for the info!

Does this also happens if initial_token is set?

Also, I am unable to understand the last line in that JIRA



> A potential complication was that seed nodes were moved without using the
> correct procedure of de-seeding them first. This was clearly wrong
> 

What is de-seeding and why would it cause this problem? Relation of seeding
and auto_bootstrap always confuses me. If and when you have time can you
please explain it to me.

Thanks

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