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https://issues.apache.org/jira/browse/CASSANDRA-10789?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16461961#comment-16461961
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Damien Stevenson commented on CASSANDRA-10789:
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I have developed some code to test this out.
Killing individual sessions doesn't really work well as the driver's
reconnection policy can immediately create another session and there is little
to no interruption to the client.
I have been testing a feature to blacklist one or more IP addresses/hostnames.
If a hostname is blacklisted, it will immediately close any existing
connections to that hostname and continue to block any new connections. The
hostname will be blocked until Cassandra restarts or the hostname is
"un-blacklisted".
What do you people think about this implementation?
I plan to have a patch available soon.
> Allow DBAs to kill individual client sessions without bouncing JVM
> ------------------------------------------------------------------
>
> Key: CASSANDRA-10789
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10789
> Project: Cassandra
> Issue Type: Improvement
> Components: Coordination
> Reporter: Wei Deng
> Priority: Major
> Fix For: 4.x
>
>
> In production, there could be hundreds of clients connected to a Cassandra
> cluster (maybe even from different applications), and if they use DataStax
> Java Driver, each client will establish at least one TCP connection to a
> Cassandra server (see
> https://datastax.github.io/java-driver/2.1.9/features/pooling/). This is all
> normal and at any given time, you can indeed see hundreds of ESTABLISHED
> connections to port 9042 on a C* server (from netstat -na). The problem is
> that sometimes when a C* cluster is under heavy load, when the DBA identifies
> some client session that sends abusive amount of traffic to the C* server and
> would like to stop it, they would like a lightweight approach rather than
> shutting down the JVM or rolling restart the whole cluster to kill all
> hundreds of connections in order to kill a single client session. If the DBA
> had root privilege, they would have been able to do something at the OS
> network level to achieve the same goal but oftentimes enterprise DBA role is
> separate from OS sysadmin role, so the DBAs usually don't have that privilege.
> This is especially helpful when you have a multi-tenant C* cluster and you
> want to have the impact for handling such client to be minimal to the other
> applications. This feature (killing individual session) seems to be a common
> feature in other databases (regardless of whether the client has some
> reconnect logic or not). It could be implemented as a JMX MBean method and
> exposed through nodetool to the DBAs.
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