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ASF GitHub Bot commented on ZOOKEEPER-2819: ------------------------------------------- Github user shralex commented on a diff in the pull request: https://github.com/apache/zookeeper/pull/292#discussion_r124183585 --- Diff: src/java/main/org/apache/zookeeper/server/quorum/QuorumPeer.java --- @@ -1744,9 +1744,14 @@ public void setAcceptedEpoch(long e) throws IOException { public boolean processReconfig(QuorumVerifier qv, Long suggestedLeaderId, Long zxid, boolean restartLE) { InetSocketAddress oldClientAddr = getClientAddress(); + boolean isReconfigEnabled = QuorumPeerConfig.isReconfigEnabled(); // update last committed quorum verifier, write the new config to disk - // and restart leader election if config changed - QuorumVerifier prevQV = setQuorumVerifier(qv, true); + // and restart leader election if config changed. If reconfig feature is + // not enabled, just set last committed quorum verifier and bail out. + QuorumVerifier prevQV = setQuorumVerifier(qv, isReconfigEnabled); --- End diff -- The server acts according to the config it has in its quorum verifier, so setting quorum verifier overwrites the config file settings with the leader's settings > Changing membership configuration via rolling restart does not work on 3.5.x. > ----------------------------------------------------------------------------- > > Key: ZOOKEEPER-2819 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2819 > Project: ZooKeeper > Issue Type: Bug > Components: quorum, server > Affects Versions: 3.5.0, 3.5.1, 3.5.2, 3.5.3 > Reporter: Michael Han > Assignee: Michael Han > Priority: Critical > > In 3.5.x there is no easy way of changing the membership config using rolling > restarts because of the introduction of dynamic reconfig feature in > ZOOKEEPER-107, which automatically manages membership configuration > parameters. > ZOOKEEPER-2014 introduced a reconfigEnabled flag to turn on / off the > reconfig feature. We can use same flag and when it sets to false, it should > disable both in memory and on disk updates of membership configuration > information, besides disabling the reconfig commands on CLI which > ZOOKEEPER-2014 already did, so users can continue using rolling restarts if > needed. > We should also document explicitly the support of membership changes via > rolling restarts will be deprecated at what release time frame and promote > reconfig as the replacement. > The problem was raised at user mailing list by Guillermo Vega-Toro, reference > thread: > http://zookeeper-user.578899.n2.nabble.com/How-to-add-nodes-to-a-Zookeeper-3-5-3-beta-ensemble-with-reconfigEnabled-false-td7583138.html -- This message was sent by Atlassian JIRA (v6.4.14#64029)