Я реализовал пример выбора лидера куратора, который приведен в этом сайт
Вместо количества клиентов куратора я добавил только один клиент куратора следующим образом
public void selectLeader() {
CuratorFramework client = null;
try {
client = CuratorFrameworkFactory.newClient("localhost:2181", new ExponentialBackoffRetry(1000, 3));
LeaderSelectorService service = new LeaderSelectorService(client, "/leaderSelections", "LeaderElector");
client.start();
Thread.sleep(10000);
service.start();
} catch (Exception e) {
System.out.println("error"+e);
}finally
{
System.out.println("Shutting down...");
// CloseableUtils.closeQuietly(client);
}
}
public class LeaderSelectorService extends LeaderSelectorListenerAdapter implements Closeable {
private final String name;
private final LeaderSelector leaderSelector;
public LeaderSelectorService(CuratorFramework client, String path, String name) {
this.name = name;
// create a leader selector using the given path for management
// all participants in a given leader selection must use the same path
// ExampleClient here is also a LeaderSelectorListener but this isn't required
leaderSelector = new LeaderSelector(client, path, this);
// for most cases you will want your instance to requeue when it relinquishes leadership
leaderSelector.autoRequeue();
}
public void start() throws IOException
{
// the selection for this instance doesn't start until the leader selector is started
// leader selection is done in the background so this call to leaderSelector.start() returns immediately
leaderSelector.start();
}
@Override
public void takeLeadership(CuratorFramework arg0) throws Exception {
// we are now the leader. This method should not return until we want to relinquish leadership
final int waitSeconds = (int)(5 * Math.random()) + 1;
System.out.println(name + " is now the leader. Waiting " + waitSeconds + " seconds...");
//System.out.println(name + " has been leader " + leaderCount.getAndIncrement() + " time(s) before.");
try
{
Thread.sleep(TimeUnit.SECONDS.toMillis(waitSeconds));
}
catch ( InterruptedException e )
{
System.err.println(name + " was interrupted.");
Thread.currentThread().interrupt();
}
finally
{
System.out.println(name + " relinquishing leadership.\n");
}
}
@Override
public void close() throws IOException {
leaderSelector.close();
}
}
У меня есть только один экземпляр zookeeper, и я использую Zookeeper 3.4.6, curator-framework 4.0.0 и curator-recipes 4.0.0. когда я запускаю клиент, он подключается к zookeeper, и в журнале я вижу сообщение «Изменение состояния: подключено».
Затем я жду 10 секунд и начинаю выборы лидера, что неоднократно дает мне ошибку ниже.
2017-09-06 09:34:22.727 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Unable to read additional data from server sessionid 0x15e555a719d0000, likely server has closed socket, closing socket connection and attempting reconnect
2017-09-06 09:34:22.830 INFO 1228 --- [c-1-EventThread] o.a.c.f.state.ConnectionStateManager : State change: SUSPENDED
2017-09-06 09:34:23.302 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2017-09-06 09:34:23.303 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Socket connection established, initiating session, client: /127.0.0.1:49594, server: localhost/127.0.0.1:2181
2017-09-06 09:34:23.305 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x15e555a719d0000, negotiated timeout = 120000
2017-09-06 09:34:23.305 INFO 1228 --- [c-1-EventThread] o.a.c.f.state.ConnectionStateManager : State change: RECONNECTED
2017-09-06 09:34:23.310 WARN 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Session 0x15e555a719d0000 for server localhost/127.0.0.1:2181, unexpected error, closing socket connection and attempting reconnect
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method) ~[na:1.8.0_131]
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39) ~[na:1.8.0_131]
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223) ~[na:1.8.0_131]
at sun.nio.ch.IOUtil.read(IOUtil.java:192) ~[na:1.8.0_131]
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380) ~[na:1.8.0_131]
at org.apache.zookeeper.ClientCnxnSocketNIO.doIO(ClientCnxnSocketNIO.java:75) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:363) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1214) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
через некоторое время он начал давать мне сообщение об ошибке ниже.
org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss
at org.apache.zookeeper.KeeperException.create(KeeperException.java:99) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.curator.framework.imps.CuratorFrameworkImpl.checkBackgroundRetry(CuratorFrameworkImpl.java:831) [curator-framework-4.0.0.jar:4.0.0]
at org.apache.curator.framework.imps.CuratorFrameworkImpl.processBackgroundOperation(CuratorFrameworkImpl.java:623) [curator-framework-4.0.0.jar:4.0.0]
at org.apache.curator.framework.imps.WatcherRemovalFacade.processBackgroundOperation(WatcherRemovalFacade.java:152) [curator-framework-4.0.0.jar:4.0.0]
at org.apache.curator.framework.imps.GetConfigBuilderImpl$2.processResult(GetConfigBuilderImpl.java:222) [curator-framework-4.0.0.jar:4.0.0]
at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:590) [zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:499) [zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
2017-09-06 09:34:31.897 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2017-09-06 09:34:31.898 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Socket connection established, initiating session, client: /127.0.0.1:49611, server: localhost/127.0.0.1:2181
2017-09-06 09:34:31.899 INFO 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x15e555a719d0000, negotiated timeout = 120000
2017-09-06 09:34:31.899 INFO 1228 --- [c-1-EventThread] o.a.c.f.state.ConnectionStateManager : State change: RECONNECTED
2017-09-06 09:34:31.907 WARN 1228 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn : Session 0x15e555a719d0000 for server localhost/127.0.0.1:2181, unexpected error, closing socket connection and attempting reconnect
java.io.IOException: Xid out of order. Got Xid 41 with err -6 expected Xid 40 for a packet with details: clientPath:/leaderSelections serverPath:/leaderSelections finished:false header:: 40,12 replyHeader:: 0,0,-4 request:: '/leaderSelections,F response:: v{}
at org.apache.zookeeper.ClientCnxn$SendThread.readResponse(ClientCnxn.java:892) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.zookeeper.ClientCnxnSocketNIO.doIO(ClientCnxnSocketNIO.java:101) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:363) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1214) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
Я попробовал несколько решений в Интернете, но мне это не удалось. Кто-нибудь знает основную причину этой проблемы.
