一、问题描述
Redis Cluster集群，当master宕机，主从切换，客户端报错 timed out
二、原因
SpringBoot2.X版本开始Redis默认的连接池都是采用的Lettuce。当节点发生改变后，Letture默认是不会刷新节点拓扑的。
三、解决方案
3.1 方案一：把lettuce换成jedis
只需要在pom.xml里调整一下依赖的引用
org.springframework.bootspring-boot-starter-data-redis2.1.5.RELEASEio.lettucelettuce-coreredis.clientsjedis3.1.0-m4
3.2 方案二：刷新节点拓扑视图
Redis节点异常，服务端的Redis集群拓扑被刷新了，Java程序没有获取到新的拓扑。
Lettuce官方文档中关于Redis Cluster的相关说明：Lettuce处理Moved和Ask永久重定向，由于命令重定向，你必须刷新节点拓扑视图。而自适应拓扑刷新（Adaptive updates）与定时拓扑刷新（Periodic updates）是默认关闭的，可以通过如下代码打开。
https://github.com/lettuce-io/lettuce-core/wiki/Redis-Cluster#user-content-refreshing-the-cluster-topology-view
修改代码如下
package com.montnets.common.redis;
import io.lettuce.core.ClientOptions;
import io.lettuce.core.cluster.ClusterClientOptions;
import io.lettuce.core.cluster.ClusterTopologyRefreshOptions;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.data.redis.RedisProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.connection.RedisClusterConfiguration;
import org.springframework.data.redis.connection.RedisNode;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.lettuce.LettuceClientConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration;
import org.springframework.stereotype.Component;
import java.time.Duration;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
@Component
public class RedisPoolConfig {
@Autowired
private RedisProperties redisProperties;
public GenericObjectPoolConfig> genericObjectPoolConfig(RedisProperties.Pool properties) {
GenericObjectPoolConfig> config = new GenericObjectPoolConfig();
config.setMaxTotal(properties.getMaxActive());
config.setMaxIdle(properties.getMaxIdle());
config.setMinIdle(properties.getMinIdle());
if (properties.getTimeBetweenEvictionRuns() != null) {
config.setTimeBetweenEvictionRunsMillis(properties.getTimeBetweenEvictionRuns().toMillis());
}
if (properties.getMaxWait() != null) {
config.setMaxWaitMillis(properties.getMaxWait().toMillis());
}
return config;
}
@Bean(destroyMethod = "destroy")
public LettuceConnectionFactory lettuceConnectionFactory() {
//开启 自适应集群拓扑刷新和周期拓扑刷新
ClusterTopologyRefreshOptions clusterTopologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
// 开启全部自适应刷新
.enableAllAdaptiveRefreshTriggers() // 开启自适应刷新,自适应刷新不开启,Redis集群变更时将会导致连接异常
// 自适应刷新超时时间(默认30秒)
.adaptiveRefreshTriggersTimeout(Duration.ofSeconds(30)) //默认关闭开启后时间为30秒
// 开周期刷新
.enablePeriodicRefresh(Duration.ofSeconds(20)) // 默认关闭开启后时间为60秒 ClusterTopologyRefreshOptions.DEFAULT_REFRESH_PERIOD 60 .enablePeriodicRefresh(Duration.ofSeconds(2)) = .enablePeriodicRefresh().refreshPeriod(Duration.ofSeconds(2))
.build();
// https://github.com/lettuce-io/lettuce-core/wiki/Client-Options
ClientOptions clientOptions = ClusterClientOptions.builder()
.topologyRefreshOptions(clusterTopologyRefreshOptions)
.build();
LettuceClientConfiguration clientConfig = LettucePoolingClientConfiguration.builder()
.poolConfig(genericObjectPoolConfig(redisProperties.getJedis().getPool()))
//.readFrom(ReadFrom.MASTER_PREFERRED)
.clientOptions(clientOptions)
.commandTimeout(redisProperties.getTimeout()) //默认RedisURI.DEFAULT_TIMEOUT 60
.build();
List clusterNodes = redisProperties.getCluster().getNodes();
Set nodes = new HashSet();
clusterNodes.forEach(address -> nodes.add(new RedisNode(address.split(":")[0].trim(), Integer.valueOf(address.split(":")[1]))));
RedisClusterConfiguration clusterConfiguration = new RedisClusterConfiguration();
clusterConfiguration.setClusterNodes(nodes);
clusterConfiguration.setPassword(RedisPassword.of(redisProperties.getPassword()));
clusterConfiguration.setMaxRedirects(redisProperties.getCluster().getMaxRedirects());
LettuceConnectionFactory lettuceConnectionFactory = new LettuceConnectionFactory(clusterConfiguration, clientConfig);
// lettuceConnectionFactory.setShareNativeConnection(false); //是否允许多个线程操作共用同一个缓存连接，默认true，false时每个操作都将开辟新的连接
// lettuceConnectionFactory.resetConnection(); // 重置底层共享连接, 在接下来的访问时初始化
return lettuceConnectionFactory;
}
}
以上就是Redis集群Lettuce主从切换问题解决方案的详细内容，更多关于Redis集群Lettuce主从切换的资料请关注IT俱乐部其它相关文章！
