/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.ha;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assume.assumeTrue;
import java.util.Collections;
import java.util.UUID;
import org.apache.commons.logging.impl.Log4JLogger;
import org.apache.hadoop.ha.ActiveStandbyElector.ActiveStandbyElectorCallback;
import org.apache.hadoop.ha.ActiveStandbyElector.State;
import org.apache.hadoop.util.ZKUtil.ZKAuthInfo;
import org.apache.hadoop.util.Shell;
import org.apache.log4j.Level;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.server.ZooKeeperServer;
import org.junit.Test;
import org.mockito.AdditionalMatchers;
import org.mockito.Mockito;
import com.google.common.primitives.Ints;
/**
* Test for {@link ActiveStandbyElector} using real zookeeper.
*/
public class TestActiveStandbyElectorRealZK extends ClientBaseWithFixes {
static final int NUM_ELECTORS = 2;
static {
((Log4JLogger)ActiveStandbyElector.LOG).getLogger().setLevel(
Level.ALL);
}
static final String PARENT_DIR = "/" + UUID.randomUUID();
ActiveStandbyElector[] electors = new ActiveStandbyElector[NUM_ELECTORS];
private byte[][] appDatas = new byte[NUM_ELECTORS][];
private ActiveStandbyElectorCallback[] cbs =
new ActiveStandbyElectorCallback[NUM_ELECTORS];
private ZooKeeperServer zkServer;
@Override
public void setUp() throws Exception {
// skip tests on Windows until after resolution of ZooKeeper client bug
assumeTrue(!Shell.WINDOWS);
super.setUp();
zkServer = getServer(serverFactory);
for (int i = 0; i < NUM_ELECTORS; i++) {
cbs[i] = Mockito.mock(ActiveStandbyElectorCallback.class);
appDatas[i] = Ints.toByteArray(i);
electors[i] = new ActiveStandbyElector(
hostPort, 5000, PARENT_DIR, Ids.OPEN_ACL_UNSAFE,
Collections.<ZKAuthInfo>emptyList(), cbs[i]);
}
}
private void checkFatalsAndReset() throws Exception {
for (int i = 0; i < NUM_ELECTORS; i++) {
Mockito.verify(cbs[i], Mockito.never()).notifyFatalError(
Mockito.anyString());
Mockito.reset(cbs[i]);
}
}
/**
* the test creates 2 electors which try to become active using a real
* zookeeper server. It verifies that 1 becomes active and 1 becomes standby.
* Upon becoming active the leader quits election and the test verifies that
* the standby now becomes active.
*/
@Test(timeout=20000)
public void testActiveStandbyTransition() throws Exception {
LOG.info("starting test with parentDir:" + PARENT_DIR);
assertFalse(electors[0].parentZNodeExists());
electors[0].ensureParentZNode();
assertTrue(electors[0].parentZNodeExists());
// First elector joins election, becomes active.
electors[0].joinElection(appDatas[0]);
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zkServer, PARENT_DIR, appDatas[0]);
Mockito.verify(cbs[0], Mockito.timeout(1000)).becomeActive();
checkFatalsAndReset();
// Second elector joins election, becomes standby.
electors[1].joinElection(appDatas[1]);
Mockito.verify(cbs[1], Mockito.timeout(1000)).becomeStandby();
checkFatalsAndReset();
// First elector quits, second one should become active
electors[0].quitElection(true);
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zkServer, PARENT_DIR, appDatas[1]);
Mockito.verify(cbs[1], Mockito.timeout(1000)).becomeActive();
checkFatalsAndReset();
// First one rejoins, becomes standby, second one stays active
electors[0].joinElection(appDatas[0]);
Mockito.verify(cbs[0], Mockito.timeout(1000)).becomeStandby();
checkFatalsAndReset();
// Second one expires, first one becomes active
electors[1].preventSessionReestablishmentForTests();
try {
zkServer.closeSession(electors[1].getZKSessionIdForTests());
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zkServer, PARENT_DIR, appDatas[0]);
Mockito.verify(cbs[1], Mockito.timeout(1000)).enterNeutralMode();
Mockito.verify(cbs[0], Mockito.timeout(1000)).fenceOldActive(
AdditionalMatchers.aryEq(appDatas[1]));
Mockito.verify(cbs[0], Mockito.timeout(1000)).becomeActive();
} finally {
electors[1].allowSessionReestablishmentForTests();
}
// Second one eventually reconnects and becomes standby
Mockito.verify(cbs[1], Mockito.timeout(5000)).becomeStandby();
checkFatalsAndReset();
// First one expires, second one should become active
electors[0].preventSessionReestablishmentForTests();
try {
zkServer.closeSession(electors[0].getZKSessionIdForTests());
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zkServer, PARENT_DIR, appDatas[1]);
Mockito.verify(cbs[0], Mockito.timeout(1000)).enterNeutralMode();
Mockito.verify(cbs[1], Mockito.timeout(1000)).fenceOldActive(
AdditionalMatchers.aryEq(appDatas[0]));
Mockito.verify(cbs[1], Mockito.timeout(1000)).becomeActive();
} finally {
electors[0].allowSessionReestablishmentForTests();
}
checkFatalsAndReset();
}
@Test(timeout=15000)
public void testHandleSessionExpiration() throws Exception {
ActiveStandbyElectorCallback cb = cbs[0];
byte[] appData = appDatas[0];
ActiveStandbyElector elector = electors[0];
// Let the first elector become active
elector.ensureParentZNode();
elector.joinElection(appData);
ZooKeeperServer zks = getServer(serverFactory);
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zks, PARENT_DIR, appData);
Mockito.verify(cb, Mockito.timeout(1000)).becomeActive();
checkFatalsAndReset();
LOG.info("========================== Expiring session");
zks.closeSession(elector.getZKSessionIdForTests());
// Should enter neutral mode when disconnected
Mockito.verify(cb, Mockito.timeout(1000)).enterNeutralMode();
// Should re-join the election and regain active
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zks, PARENT_DIR, appData);
Mockito.verify(cb, Mockito.timeout(1000)).becomeActive();
checkFatalsAndReset();
LOG.info("========================== Quitting election");
elector.quitElection(false);
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zks, PARENT_DIR, null);
// Double check that we don't accidentally re-join the election
// due to receiving the "expired" event.
Thread.sleep(1000);
Mockito.verify(cb, Mockito.never()).becomeActive();
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zks, PARENT_DIR, null);
checkFatalsAndReset();
}
@Test(timeout=15000)
public void testHandleSessionExpirationOfStandby() throws Exception {
// Let elector 0 be active
electors[0].ensureParentZNode();
electors[0].joinElection(appDatas[0]);
ZooKeeperServer zks = getServer(serverFactory);
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zks, PARENT_DIR, appDatas[0]);
Mockito.verify(cbs[0], Mockito.timeout(1000)).becomeActive();
checkFatalsAndReset();
// Let elector 1 be standby
electors[1].joinElection(appDatas[1]);
ActiveStandbyElectorTestUtil.waitForElectorState(null, electors[1],
State.STANDBY);
LOG.info("========================== Expiring standby's session");
zks.closeSession(electors[1].getZKSessionIdForTests());
// Should enter neutral mode when disconnected
Mockito.verify(cbs[1], Mockito.timeout(1000)).enterNeutralMode();
// Should re-join the election and go back to STANDBY
ActiveStandbyElectorTestUtil.waitForElectorState(null, electors[1],
State.STANDBY);
checkFatalsAndReset();
LOG.info("========================== Quitting election");
electors[1].quitElection(false);
// Double check that we don't accidentally re-join the election
// by quitting elector 0 and ensuring elector 1 doesn't become active
electors[0].quitElection(false);
// due to receiving the "expired" event.
Thread.sleep(1000);
Mockito.verify(cbs[1], Mockito.never()).becomeActive();
ActiveStandbyElectorTestUtil.waitForActiveLockData(null,
zks, PARENT_DIR, null);
checkFatalsAndReset();
}
@Test(timeout=15000)
public void testDontJoinElectionOnDisconnectAndReconnect() throws Exception {
electors[0].ensureParentZNode();
stopServer();
ActiveStandbyElectorTestUtil.waitForElectorState(
null, electors[0], State.NEUTRAL);
startServer();
waitForServerUp(hostPort, CONNECTION_TIMEOUT);
// Have to sleep to allow time for the clients to reconnect.
Thread.sleep(2000);
Mockito.verify(cbs[0], Mockito.never()).becomeActive();
Mockito.verify(cbs[1], Mockito.never()).becomeActive();
checkFatalsAndReset();
}
}