[
https://issues.apache.org/jira/browse/CASSANDRA-14779?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16704052#comment-16704052
]
Ian Cleasby commented on CASSANDRA-14779:
-----------------------------------------
Added an exception to handle the case that JMX tries to update the Snitch which
is going to effectively change the topology.
[trunk|https://github.com/apache/cassandra/compare/trunk...PenguinRage:Changing-EndpointSnitch-via-JMX-has-problems]
> Changing EndpointSnitch via JMX has problems
> --------------------------------------------
>
> Key: CASSANDRA-14779
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14779
> Project: Cassandra
> Issue Type: Bug
> Components: Distributed Metadata
> Reporter: Benedict
> Priority: Minor
> Fix For: 4.x
>
>
> The snitch can be set via StorageService over JMX, for what reason I’m
> unsure. If this were to happen, we might encounter the following problems:
> * If the effective local DC were to change, we would not update it. Perhaps
> changing the local DC of a node should be rejected and cause it to fail, but
> presently, it would simply result in our disagreeing with the snitch.
> * During the transition, routing of queries might be broken, as we fetch the
> snitch multiple times in different locations when deciding where to route our
> query and writes. It’s not clear what the outcome of a discordant view of the
> ring would be.
> Probably, changing this information in a live cluster is dangerous and we
> should actually reject any effective changes to rack, or DC for any node. But
> presently we don’t seem to corroborate that this information remains the
> same. We don’t seem to perform any cluster wide confirmation that this data
> is consistent, generally, which perhaps we should also consider.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
