Thanks @szetszwo for the clarification !
It really helps. Shashi and I went through code yesterday and got the same
conclusion, yet not verified.
The setConfiguration implementation rigoriously complies with the joint
consensus algorithms, which simplies the design of bootstrap a new empty SCM in
the HA mode.
BR Glen
At 2021-02-04 17:33:18, "Tsz Wo Sze" <[email protected]> wrote:
>You are right that there is no un-available time during the membership
>change. I just have tested it using
>RaftReconfigurationBaseTest.testBootstrapReconfWithSingleNodeAddOne() as
>below.
>
>*+++
>b/ratis-server/src/test/java/org/apache/ratis/server/impl/RaftReconfigurationBaseTest.java*
>
>@@ -352,9 +352,15 @@ public abstract class
>RaftReconfigurationBaseTest<CLUSTER extends MiniRaftCluste
>
> clientThread.start();
>
>
>
> if (!startNewPeer) {
>
>- final TimeDuration delay = FIVE_SECONDS;
>
>- LOG.info("delay {} and start new peer(s): {}", delay,
>c1.newPeers);
>
>- delay.sleep();
>
>+ final int delayInSeconds = 5;
>
>+ LOG.info("delay {}s and start new peer(s): {}", delayInSeconds,
>c1.newPeers);
>
>+ for (int i = 0; i < delayInSeconds; i++) {
>
>+ final SimpleMessage message = new SimpleMessage("async" + i);
>
>+ final RaftClientReply reply =
>client.async().send(message).get();
>
>+ LOG.info("Received reply {} for {}", reply, message);
>
>+ Assert.assertTrue(reply.isSuccess());
>
>+ ONE_SECOND.sleep();
>
>+ }
>
> for(RaftPeer p : c1.newPeers) {
>
> cluster.restartServer(p.getId(), true);
>
> }
>
>Hope it helps.
>Tsz-Wo
>
>On Wed, Feb 3, 2021 at 3:30 PM GlenGeng <[email protected]> wrote:
>
>>
>>
>> Hi all,
>>
>>
>> I have a question about the membership change implemented by Ratis.
>>
>>
>> Ratis implements the joint consensus (the complex one, according to the
>> add/remove one server each time), and use LeaderStateImpl#stagingState to
>> maintain the catch up progess of the new added raft node, thus won't append
>> the OldNewConf into raft log until the new added peer catch up.
>>
>>
>> I consider there should be no un-available time during the membership
>> change theoriocitally, even trying to change a single node cluster to a two
>> node cluster, is that right ?
>>
>>
>> Thanks!
>> BR Glen
>>
>>
