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https://issues.apache.org/jira/browse/KUDU-2914?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16941152#comment-16941152
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Alexey Serbin commented on KUDU-2914:
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Some more information just for better perspective. Let's take a look at the
bigger picture in case of the 3-4-3 replica management scheme. I think we can
ignore the old 3-2-3 scheme which was used in Kudu v1.6 and earlier.
In case of the 3-4-3 scheme, if it's necessary to remove a tablet replica from
a tablet server, it's enough to mark the replica with the {{REPLACE}} attribute
(see {{RaftConsensus::BulkChangeConfig()}}, {{RaftPeerAttrsPB::replace}} in
{{src/kudu/consensus/metadata.proto}}). Once the {{REPLACE}} attribute is set,
the logic in the master automatically creates a non-voter replacement replica
elsewhere, trying to satisfy the placement policy and keeping the tablet
distribution as balanced as possible. Eventually, when a new replica is
promoted to a voter, the source replica is removed.
If there were a way to mark a tablet server as not available for placement of
new tablet replicas (something like already implemented with
https://github.com/apache/kudu/commit/e8362ca1bb48ed0150cf134d93899d7a2f74caf3
as a part of [KUDU-2069|https://issues.apache.org/jira/browse/KUDU-2069]), it
would be necessary to simply mark all replicas at the tablet server with the
{{REPLACE}} attribute and await until there is no tablet replicas left at the
tablet server.
> Rebalance tool support moving replicas from some specific tablet servers
> ------------------------------------------------------------------------
>
> Key: KUDU-2914
> URL: https://issues.apache.org/jira/browse/KUDU-2914
> Project: Kudu
> Issue Type: Improvement
> Components: CLI
> Reporter: YifanZhang
> Assignee: YifanZhang
> Priority: Minor
>
> When we need to remove some tservers from a kudu cluster (maybe just for
> saving resources or replacing these servers with new servers), it's better to
> move all replicas on these tservers to other tservers in a cluster in
> advance, instead of waiting for all replicas kicked out and evicting new
> replicas. This can be achieved by rebalance tool supporting specifying
> 'blacklist_tservers'.
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