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https://issues.apache.org/jira/browse/IGNITE-16011?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vyacheslav Koptilin updated IGNITE-16011:
-----------------------------------------
    Fix Version/s: 3.0.0-alpha5

> Start new rebalance round, when partition assignments updated
> -------------------------------------------------------------
>
>                 Key: IGNITE-16011
>                 URL: https://issues.apache.org/jira/browse/IGNITE-16011
>             Project: Ignite
>          Issue Type: Task
>            Reporter: Kirill Gusakov
>            Assignee: Kirill Gusakov
>            Priority: Major
>              Labels: ignite-3
>             Fix For: 3.0.0-alpha5
>
>          Time Spent: 8h
>  Remaining Estimate: 0h
>
> When partition assignments are updated, we need to start raft changePeers and 
> handle failover scenarios.
> When metastore event about partition assignments updates received we need to:
>  - Start all needed nodes 
> {code:java}
>  partition.assignments.pending / partition.assignments.stable{code}
>  - After successful starts - check if current node is the leader of raft 
> group (leader response must be updated by current term) and 
> changePeers(leaderTerm, peers). changePeers from old terms must be skipped.
> Also, we need the propagation of some new events from the raft side:
>  * {{onLeaderElected(boolean configurationChangeInProgress)}} - must be 
> executed from the new leader when raft group changes the leader. Maybe we 
> actually need to also check if a new lease is received - we need to 
> investigate.
>  * {{onChangePeersError(errorContext)}} - must be executed when any errors 
> during changePeers occurred
>  * {{onChangePeersCommitted(peers)}} - must be executed with the list of new 
> peers when changePeers has successfully done.
> and handle them by appropriate way:
>  * {{{}onLeaderElected({}}}{{{}configurationChangeInProgress{}}}{{{}){}}} - 
> we need to:
>  ** if {{configurationChangeInProgress}} == false and pending/planned 
> assignments not empty - run new changePeers. If true, do nothing.}}
>  * {{onChangePeersError(errorContext)}} - run failover logic
>  * {{onChangePeersCommitted(peers)}} - check if planned assignments is not 
> empty and move it to pending.
>  * 
>  -- Update pending and stable partitions assignments:
> {code:java}
> metastoreInvoke: \\ atomic
>     // Here we can check invariant that pending is empty, but planned is not 
> is impossible
>     partition.assignments.stable = appliedPeers
>     if empty(partition.assignments.planned):
>         partition.assignments.pending = empty
>     else:
>         partition.assignments.pending = partition.assignments.planned {code}
> When {{partition.assignments.stable}} updated, we need to:
>  * Replace current raft client with new one, with appropriate peers
>  * Stop unneeded raft node
>  
> (Phase 1)



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