java - 如果集群中的第一个节点关闭，Redis 客户端 (Redission) 将停止工作

Question

我有一个 Master Master redis 集群 3 (node1,node2,node3)。我正在使用 Redission用于跨 JVM 的分布式锁定的客户端。现在根据RedLock由 Redission 实现的算法，它尝试在大多数节点中获取锁(在我的例子中，2 是大多数节点)，它使用循环算法进行负载平衡。现在，如果我们阻止节点 2 或节点 3 的网络，这种锁定机制可以正常工作。但是如果我们阻止节点 1 的网络，那么它将失败并出现以下错误

Exception in thread "main" org.redisson.client.RedisNodeNotFoundException: No node for slot: 15087 and command (EVAL)
at org.redisson.connection.MasterSlaveConnectionManager.getEntry(MasterSlaveConnectionManager.java:578)
at org.redisson.connection.MasterSlaveConnectionManager.connectionWriteOp(MasterSlaveConnectionManager.java:563)
at org.redisson.command.CommandAsyncService.async(CommandAsyncService.java:368)
at org.redisson.command.CommandAsyncService.evalAsync(CommandAsyncService.java:334)
at org.redisson.command.CommandAsyncService.evalWriteAsync(CommandAsyncService.java:282)
at org.redisson.RedissonLock.tryLockInnerAsync(RedissonLock.java:207)
at org.redisson.RedissonLock.tryAcquire(RedissonLock.java:139)
at org.redisson.RedissonLock.tryLock(RedissonLock.java:225)
at com.seamless.common.cache.distributed.LockManager.getLock(LockManager.java:37)
at com.testlock.app.App.main(App.java:34)

下面是我如何创建 Redission 客户端

    import java.util.List;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;
import org.redisson.ClusterServersConfig;
import org.redisson.Config;
import org.redisson.ReadMode;
import org.redisson.Redisson;
import org.redisson.RedissonClient;
import org.redisson.core.RLock;

public class LockManager {


private static final Logger LOG = Logger.getLogger(LockManager.class);


private RedissonClient redissonClient;

LockManager(List<String> nodes){
    Config config = new Config();
    ClusterServersConfig serverConfig=config.useClusterServers();
    serverConfig.setReadMode(ReadMode.MASTER);
    for(String node :nodes){
        serverConfig.addNodeAddress(node);
    }
    redissonClient = Redisson.create(config);

}

public boolean getLock(final String lockKey,int timeout){
    RLock lock=redissonClient.getLock(lockKey);
    try {
        return lock.tryLock(0, timeout, TimeUnit.MILLISECONDS);
    } catch (InterruptedException e) {
        LOG.error("Error getting lock "+e.getMessage());
    }
    return false;
}   

public void releaseLock(final String lockKey){
    RLock lock=redissonClient.getLock(lockKey);
    if(lock.isHeldByCurrentThread())
        lock.unlock();
}
}

Answer 1

你必须使用 RedissonRedLock 和 RedLock 算法的 3 个锁:

RLock lock1 = redisson.getLock("lock1");
RLock lock2 = redisson.getLock("lock2");
RLock lock3 = redisson.getLock("lock3");

RedissonRedLock lock = new RedissonRedLock(lock1, lock2, lock3);
lock.lock();

//...

lock.unlock();