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https://issues.apache.org/jira/browse/ZOOKEEPER-2953?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16291163#comment-16291163
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ASF GitHub Bot commented on ZOOKEEPER-2953:
-------------------------------------------
Github user afine commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/432#discussion_r156999341
--- Diff:
src/java/test/org/apache/zookeeper/server/quorum/QuorumPeerMainTest.java ---
@@ -335,6 +336,100 @@ public void testHighestZxidJoinLate() throws
Exception {
output[0], 2);
}
+ /**
+ * This test validates that if a quorum member determines that it is
leader without the support of the rest of the
+ * quorum (the other members do not believe it to be the leader) it
will stop attempting to lead and become a follower.
+ *
+ * @throws IOException
+ * @throws InterruptedException
+ */
+ @Test
+ public void testElectionFraud() throws IOException,
InterruptedException {
+ // capture QuorumPeer logging
+ Layout layout =
Logger.getRootLogger().getAppender("CONSOLE").getLayout();
+ ByteArrayOutputStream os = new ByteArrayOutputStream();
+ WriterAppender appender = new WriterAppender(layout, os);
+ appender.setThreshold(Level.INFO);
+ Logger qlogger = Logger.getLogger(QuorumPeer.class);
+ qlogger.addAppender(appender);
+
+ int numServers = 3;
+
+ // used for assertions later
+ boolean foundLeading = false;
+ boolean foundLooking = false;
+ boolean foundFollowing = false;
+
+ try {
+ // spin up a quorum, we use a small ticktime to make the test
run faster
+ Servers servers = LaunchServers(numServers, 500);
+
+ // find the leader
+ int trueLeader = -1;
+ for (int i = 0; i < numServers; i++) {
+ if (servers.mt[i].main.quorumPeer.leader != null) {
+ trueLeader = i;
+ }
+ }
+ Assert.assertTrue("There should be a leader", trueLeader >= 0);
+
+ // find a follower
+ int falseLeader = (trueLeader + 1) % numServers;
+
Assert.assertTrue(servers.mt[falseLeader].main.quorumPeer.follower != null);
--- End diff --
fixed
> Flaky Test: testNoLogBeforeLeaderEstablishment
> ----------------------------------------------
>
> Key: ZOOKEEPER-2953
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2953
> Project: ZooKeeper
> Issue Type: Bug
> Affects Versions: 3.5.3, 3.4.11, 3.6.0
> Reporter: Abraham Fine
> Assignee: Abraham Fine
>
> testNoLogBeforeLeaderEstablishment has been flaky on 3.4, 3.5, and master for
> quite awhile. My understanding is that the purpose of the test is to make
> sure that a server receives support from the quorum before changing the epoch
> and acting as leader.
> There are a couple issues with the test in its current state. First, the
> assertions the test makes are not always true. It is possible, if the
> zookeeper database is not cleared, for a follower to be ahead of a leader
> when the quorum is shutdown. That follower will then likely become leader
> when the quorum is restarted. This is the cause of the flaky behavior.
> Second, the test does not appear to create the conditions it wants to test
> for. Since, ZOOKEEPER-335 (specifically the ZOOKEEPER-1081 subtask) we take
> the epoch into consideration in {{FastLeaderElection}} so the test no longer
> "believes it is the leader once it recovers".
> After discussing the issue offline with [~phunt] we decided it would still be
> valuable to test the situation where a server is elected leader without the
> support of the quorum. So I removed {{testNoLogBeforeLeaderEstablishment}}
> and created a new test called {{testElectionFraud}}.
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