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From "Robert Coli (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-4162) nodetool disablegossip does not prevent gossip delivery of writes via already-initiated hinted handoff
Date Wed, 02 May 2012 19:40:50 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-4162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13266856#comment-13266856
] 

Robert Coli commented on CASSANDRA-4162:
----------------------------------------

"If you're hung up on the nodetool help description, let's fix that."

That's sorta my issue. What would we fix it to say?

"
disablegossip - Disable gossip (marking the node possibly mostly dead now, definitely all
dead at some unspecified time)
"
OR
"
disablegossip - Disable gossip but don't interrupt pre-existing Repair or Hinted Handoff operations
on port 7000
"
OR
"
disablegossip - Disable gossip
"

The lack of a simple one-liner that unambiguously summarizes the resulting state after "disablegossip"
suggests that the state is unclear.

The last one is clearest but suffers from a requirement of specific knowledge regarding what
other write traffic goes over port 7000. I believe this is the reason that whomever created
the parenthetical "(effectively rendering a node dead)" felt the need to specify what disabling
gossip might be used for as a logical operation. 

I think when people use disablegossip to shut off gossip, they want their node to be running,
but otherwise dead from the perspective of other nodes, immediately. They do not, I think,
want it "mostly dead now, all dead at some unspecified future time."

(OT : glad to hear it re: CASSANDRA-2392, seems like a reasonable approach to a current pain
point for operators :D)
                
> nodetool disablegossip does not prevent gossip delivery of writes via already-initiated
hinted handoff
> ------------------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-4162
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4162
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.0.9
>         Environment: reported on IRC, believe it was a linux environment, nick "rhone",
cassandra 1.0.8
>            Reporter: Robert Coli
>            Priority: Minor
>              Labels: gossip
>
> This ticket derives from #cassandra, aaron_morton and I assisted a user who had run "disablethrift"
and "disablegossip" and was confused as to why he was seeing writes to his node.
> Aaron and I went through a series of debugging questions, user verified that there was
traffic on the gossip port. His node was showing as down from the perspective of other nodes,
and nodetool also showed that gossip was not active.
> Aaron read the code and had the user turn debug logging on. The user saw Hinted Handoff
messages being delivered and Aaron confirmed in the code that a hinted handoff delivery session
only checks gossip state when it first starts. As a result, it will continue to deliver hints
and disregard gossip state on the target node.
> per nodetool docs
> "
> disablegossip          - Disable gossip (effectively marking the node dead)
> "
> I believe most people will be using disablegossip and disablethrift for operational reasons,
and propose that they do not expect HH delivery to continue, via gossip, when they have run
"disablegossip".

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