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https://issues.apache.org/jira/browse/CASSANDRA-10134?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15254689#comment-15254689
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Joel Knighton commented on CASSANDRA-10134:
-------------------------------------------
CI looks good.
I really like the route you took here - simple and separates things that have
no business being conflated. I'm not worried about the slight change in
semantics of isInitialized() - as you mentioned, there are existing methods to
obtain gossip status.
There's a bit of an interesting situation, that if anything, reinforces your
point that the semantics were unclear. In
{{DynamicEndpointSnitch.updateScores()}}, we checked the initialization status
of StorageService before proceeding. I was curious whether this was intended to
be coupled to gossip or StorageService initialization; history suggests that
the intent was to couple it to StorageService initialization to accommodate
weird singleton initialization patterns which I believe are no longer relevant
([CASSANDRA-1756]). That said, your patch coupling it to gossip preserves
existing behavior, so that change in semantics doesn't particularly concern me.
On the other hand, if you want to change that check to
{{StorageService.isInitialized()}} and rerun CI, that would also work with me.
Your call [~beobal]. In either case, I think a follow-up investigating whether
the check is safe to remove is worthwhile.
If you opt to keep the check coupled to {{isGossipActive()}}, feel free to
commit.
> Always require replace_address to replace existing address
> ----------------------------------------------------------
>
> Key: CASSANDRA-10134
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10134
> Project: Cassandra
> Issue Type: Improvement
> Components: Distributed Metadata
> Reporter: Tyler Hobbs
> Assignee: Sam Tunnicliffe
> Labels: docs-impacting
> Fix For: 3.x
>
>
> Normally, when a node is started from a clean state with the same address as
> an existing down node, it will fail to start with an error like this:
> {noformat}
> ERROR [main] 2015-08-19 15:07:51,577 CassandraDaemon.java:554 - Exception
> encountered during startup
> java.lang.RuntimeException: A node with address /127.0.0.3 already exists,
> cancelling join. Use cassandra.replace_address if you want to replace this
> node.
> at
> org.apache.cassandra.service.StorageService.checkForEndpointCollision(StorageService.java:543)
> ~[main/:na]
> at
> org.apache.cassandra.service.StorageService.prepareToJoin(StorageService.java:783)
> ~[main/:na]
> at
> org.apache.cassandra.service.StorageService.initServer(StorageService.java:720)
> ~[main/:na]
> at
> org.apache.cassandra.service.StorageService.initServer(StorageService.java:611)
> ~[main/:na]
> at
> org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:378)
> [main/:na]
> at
> org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:537)
> [main/:na]
> at
> org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:626)
> [main/:na]
> {noformat}
> However, if {{auto_bootstrap}} is set to false or the node is in its own seed
> list, it will not throw this error and will start normally. The new node
> then takes over the host ID of the old node (even if the tokens are
> different), and the only message you will see is a warning in the other
> nodes' logs:
> {noformat}
> logger.warn("Changing {}'s host ID from {} to {}", endpoint, storedId,
> hostId);
> {noformat}
> This could cause an operator to accidentally wipe out the token information
> for a down node without replacing it. To fix this, we should check for an
> endpoint collision even if {{auto_bootstrap}} is false or the node is a seed.
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