ELECTION: start / stop elections based on view changes about jgroups-raft HOT 9 CLOSED

No need to mark views as special entries in the log

Can you explain? I think you still need this for dynamic membership changes. Or does JGroups provide some persistent storage that makes it unnecessary?

https://github.com/belaban/jgroups-raft/blob/master/doc/design/Election.txt

That link's broken.

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Give me a few days to complete the design document (it's on a separate branch), and I'd be happy to get your feedback.
Once I have the full algorithm down, I'll try to model this in PlusCal/TLA+ to see if the model check reveals issues with this.

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@belaban sounds good, looking forward to seeing it.

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Need to rethink this; as #21 changed things slightly.

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@belaban, any update with such issue ? we're looking forward to some raft implementation, hope 0.4 released not long in the future with those issues fixed and completed.

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Sorry, but jgroups-raft has been dormant for a while now, and I don't expect to be able to spend much time on it in the near future.

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Hi @belaban, this is pretty much what we discussed over IRC, were you able to finish the PlusCal/TLA+ modelling?

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Hi @valdar Andrea: nope

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OK, I finally changed this to take advantage of JGroups views:

• An election is started only on a view change, by the coordinator
• When the majority is reached, the coord solicits votes from all members
• The member with the highest term (longest log) wins and becomes leader
• If all logs are equal, then the leader is the oldest member (the coord)
• Details are in [1]

This has a few advantages:

• No election / heartbeat timers -> no concurrent elections and no constant traffic to prevent followers from becoming candidates
• As a matter of fact, Candidate has been removed: we only have Leaders and Followers

The outcome should be the same as the original Raft election algorithm.

[1] https://github.com/belaban/jgroups-raft/blob/master/doc/design/Election.txt

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