[jira] [Comment Edited] (ARTEMIS-2716) Implements pluggable Quorum Vote

["Francesco Nigro (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARTEMIS-2716?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17362898#comment-17362898 ] 

Francesco Nigro edited comment on ARTEMIS-2716 at 6/14/21, 10:58 AM:
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I'm going to:
# remove the initial loop on primary start: a primary start that check for live server isn't supposed to be a non-admin automatic restart, especially if the broker was stopped because of some failure: need inspection of the state of the journal/machine and an admin would likely prefer an all-or-nothing (re)start operation 
ie start broker and await failback (or just become a backup) to happen
# deprecate/document allow-failback: allow-failback == false turn a failing-back primary into a backup that can just error out on failover errors 

NOTE: 
For the latter, in the classic replication a master acting as a backup just forget its Node ID if any error happen during a failover and restart as an empty backup.
It's dangerous because on broker restart, the broker got a different NodeID and can always succeed to become live (!!).


was (Author: nigrofranz):
I'm going to:
# remove the initial loop on primary start: a primary start that check for live server isn't supposed to be a non-admin automatic restart, especially if the broker was stopped because of some failure: need inspection of the state of the journal/machine and an admin would likely prefer an all-or-nothing (re)start operation 
ie start broker and await failback (or just become a backup) to happen
# deprecate allow-failback: allow-failback == false turn a failing-back primary into a backup that can just error out on failover errors 

NOTE: 
For the latter, in the classic replication a master acting as a backup just forget its Node ID if any error happen during a failover and restart as an empty backup.
It's dangerous because on broker restart, the broker got a different NodeID and can always succeed to become live (!!).

> Implements pluggable Quorum Vote
> --------------------------------
>
>                 Key: ARTEMIS-2716
>                 URL: https://issues.apache.org/jira/browse/ARTEMIS-2716
>             Project: ActiveMQ Artemis
>          Issue Type: New Feature
>            Reporter: Francesco Nigro
>            Assignee: Francesco Nigro
>            Priority: Major
>         Attachments: backup.png, primary.png
>
>          Time Spent: 16h
>  Remaining Estimate: 0h
>
> This task aim to ideliver a new Quorum Vote mechanism for artemis with the objectives:
> # to make it pluggable
> # to cleanly separate the election phase and the cluster member states
> # to simplify most common setups in both amount of configuration and requirements (eg "witness" nodes could be implemented to support single master-slave pairs)
> Post-actions to help people adopt it, but need to be thought upfront:
> # a clean upgrade path for current HA replication users
> # deprecate or integrate the current HA replication into the new version



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