@Test
public void testOnConnectedAndDisconnecting() throws Exception {
// Logger.getRootLogger().setLevel(Level.INFO);
String className = TestHelper.getTestClassName();
String methodName = TestHelper.getTestMethodName();
String clusterName = className + "_" + methodName;
int n = 2;
System.out.println("START " + clusterName + " at " + new Date(System.currentTimeMillis()));
TestHelper.setupCluster(
clusterName,
_zkaddr,
12918, // participant port
"localhost", // participant name prefix
"TestDB", // resource name prefix
1, // resources
32, // partitions per resource
n, // number of nodes
2, // replicas
"MasterSlave",
true); // do rebalance
// create connection
HelixConnection connection = new ZkHelixConnection(_zkaddr);
connection.connect();
// start controller
ClusterId clusterId = ClusterId.from(clusterName);
ControllerId controllerId = ControllerId.from("controller");
HelixController controller = connection.createController(clusterId, controllerId);
controller.start();
// check leader znode exists
HelixDataAccessor accessor = connection.createDataAccessor(clusterId);
PropertyKey.Builder keyBuilder = accessor.keyBuilder();
LiveInstance leader = accessor.getProperty(keyBuilder.controllerLeader());
Assert.assertNotNull(leader);
Assert.assertEquals(leader.getInstanceName(), controllerId.stringify());
// stop participant
controller.stop();
// check leader znode is gone
Assert.assertNull(accessor.getProperty(keyBuilder.controllerLeader()));
// clean up
connection.disconnect();
System.out.println("END " + clusterName + " at " + new Date(System.currentTimeMillis()));
}
/**
* Remove leader znode externally should invoke another round of leader-election this simulates
* the race condition in {@link
* ZkHelixLeaderElection#onControllerChange(org.apache.helix.NotificationContext)}
*
* @throws Exception
*/
@Test
public void testRemoveLeaderZnode() throws Exception {
// Logger.getRootLogger().setLevel(Level.INFO);
String className = TestHelper.getTestClassName();
String methodName = TestHelper.getTestMethodName();
String clusterName = className + "_" + methodName;
int n = 2;
System.out.println("START " + clusterName + " at " + new Date(System.currentTimeMillis()));
TestHelper.setupCluster(
clusterName,
_zkaddr,
12918, // participant port
"localhost", // participant name prefix
"TestDB", // resource name prefix
1, // resources
32, // partitions per resource
n, // number of nodes
2, // replicas
"MasterSlave",
true); // do rebalance
// create connection
HelixConnection connection = new ZkHelixConnection(_zkaddr);
connection.connect();
// start controller
ClusterId clusterId = ClusterId.from(clusterName);
final ControllerId controllerId = ControllerId.from("controller");
// start controller
HelixController controller = connection.createController(clusterId, controllerId);
controller.start();
// check live-instance znode for localhost_12918 exists
final HelixDataAccessor accessor = new ZKHelixDataAccessor(clusterName, _baseAccessor);
final PropertyKey.Builder keyBuilder = accessor.keyBuilder();
LiveInstance leader = accessor.getProperty(keyBuilder.controllerLeader());
Assert.assertNotNull(leader);
Assert.assertEquals(leader.getInstanceName(), controllerId.stringify());
// remove leader znode externally
accessor.removeProperty(keyBuilder.controllerLeader());
// verify leader is re-elected
boolean result =
TestHelper.verify(
new TestHelper.Verifier() {
@Override
public boolean verify() throws Exception {
LiveInstance leader = accessor.getProperty(keyBuilder.controllerLeader());
if (leader == null) {
return false;
}
return leader.getInstanceName().equals(controllerId.stringify());
}
},
3 * 1000);
Assert.assertTrue(result, "Fail to re-elect a new leader");
// clean up
connection.disconnect();
// check leader znode is gone
Assert.assertNull(accessor.getProperty(keyBuilder.controllerLeader()));
System.out.println("END " + clusterName + " at " + new Date(System.currentTimeMillis()));
}