Github user anmolnar commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/432#discussion_r156660196
--- 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);
+
+ // to keep the quorum peer running and force it to go into the
looking state, we kill leader election
+ // and close the connection to the leader
+ servers.mt[falseLeader].main.quorumPeer.electionAlg.shutdown();
+
servers.mt[falseLeader].main.quorumPeer.follower.getSocket().close();
+
+ // wait for the falseLeader to disconnect
+ waitForOne(servers.zk[falseLeader], States.CONNECTING);
+
+ // convince falseLeader that it is the leader
+
servers.mt[falseLeader].main.quorumPeer.setPeerState(QuorumPeer.ServerState.LEADING);
+
+ // provide time for the falseleader to realize no followers have
connected
+ // (this is twice the timeout used in Leader#getEpochToPropose)
+ Thread.sleep(2 *
servers.mt[falseLeader].main.quorumPeer.initLimit *
servers.mt[falseLeader].main.quorumPeer.tickTime);
+
+ // Restart leader election
+ servers.mt[falseLeader].main.quorumPeer.startLeaderElection();
--- End diff --
I wonder if this one has to be called explicitly.
The peer should automatically realise that it's no longer the leader, stop
leading and start leader election (which is basically looking). That's what
this test is intended to validate and shouldn't be started explicitly.
Correct me if I'm wrong.
---
