java使用Redis7--分布式存储并实现sentinel主从自动切换

前面实现了分布式存储，也实现了sentinel单点故障时主从自动切换，现在还需要一种机制，实现分布式存储下，单点故障时的主从自动切换。

Server配置

# cd /usr/redis/src/test

创建4个配置文件

redis6378.conf redis6379.conf redis6380.conf redis6381.conf

启动4个服务

# redis-server redis6378.conf &

# redis-server redis6379.conf &

# redis-server redis6380.conf &

# redis-server redis6381.conf &

登陆6379设置master：6378

# redis-cli -p 6379

127.0.0.1:6379> slaveof 127.0.0.1 6378

登陆6381设置master：6380

# redis-cli -p 6381

127.0.0.1:6381> slaveof 127.0.0.1 6380

创建sentinel配置文件,同时监控2个分片

# vim sentinel29379.conf

port 26379
dir "/tmp"
#shard1
sentinel monitor shard1 192.168.77.135 6378 2
sentinel down-after-milliseconds shard1 30000
sentinel parallel-syncs shard1 1
sentinel failover-timeout shard1 180000

#shard2
sentinel monitor shard2 192.168.77.136 6380 2
sentinel down-after-milliseconds shard2 30000
sentinel parallel-syncs shard2 1
sentinel failover-timeout shard2 180000

# wq

创建sentinel29380.conf 修改port 26380 

创建sentinel29381.conf 修改port 26381

启动sentlnel

#redis-sentinel sentinel26379.conf & 

#redis-sentinel sentinel26380.conf & 

#redis-sentinel sentinel26381.conf & 

java端实现

package redis;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.logging.Logger;
import java.util.regex.Pattern;

import org.apache.commons.pool2.PooledObject;
import org.apache.commons.pool2.PooledObjectFactory;
import org.apache.commons.pool2.impl.DefaultPooledObject;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;

import redis.clients.jedis.HostAndPort;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPubSub;
import redis.clients.jedis.JedisShardInfo;
import redis.clients.jedis.Protocol;
import redis.clients.jedis.ShardedJedis;
import redis.clients.jedis.exceptions.JedisConnectionException;
import redis.clients.util.Hashing;
import redis.clients.util.Pool;

public class ShardedJedisSentinelPool extends Pool<ShardedJedis> {

    public static final int MAX_RETRY_SENTINEL = 10;

    protected final Logger log = Logger.getLogger(getClass().getName());

    protected GenericObjectPoolConfig poolConfig;

    protected int timeout = Protocol.DEFAULT_TIMEOUT;

    private int sentinelRetry = 0;

    protected String password;

    protected int database = Protocol.DEFAULT_DATABASE;

    protected Set<MasterListener> masterListeners = new HashSet<MasterListener>();

    private volatile List<HostAndPort> currentHostMasters;

    public ShardedJedisSentinelPool(List<String> masters, Set<String> sentinels) {
        this(masters, sentinels, new GenericObjectPoolConfig(), Protocol.DEFAULT_TIMEOUT, null, Protocol.DEFAULT_DATABASE);
    }

    public ShardedJedisSentinelPool(List<String> masters, Set<String> sentinels, String password) {
        this(masters, sentinels, new GenericObjectPoolConfig(), Protocol.DEFAULT_TIMEOUT, password);
    }

    public ShardedJedisSentinelPool(final GenericObjectPoolConfig poolConfig, List<String> masters, Set<String> sentinels) {
        this(masters, sentinels, poolConfig, Protocol.DEFAULT_TIMEOUT, null, Protocol.DEFAULT_DATABASE);
    }

    public ShardedJedisSentinelPool(List<String> masters, Set<String> sentinels, final GenericObjectPoolConfig poolConfig, int timeout, final String password) {
        this(masters, sentinels, poolConfig, timeout, password, Protocol.DEFAULT_DATABASE);
    }

    public ShardedJedisSentinelPool(List<String> masters, Set<String> sentinels, final GenericObjectPoolConfig poolConfig, final int timeout) {
        this(masters, sentinels, poolConfig, timeout, null, Protocol.DEFAULT_DATABASE);
    }

    public ShardedJedisSentinelPool(List<String> masters, Set<String> sentinels, final GenericObjectPoolConfig poolConfig, final String password) {
        this(masters, sentinels, poolConfig, Protocol.DEFAULT_TIMEOUT, password);
    }

    public ShardedJedisSentinelPool(List<String> masters, Set<String> sentinels, final GenericObjectPoolConfig poolConfig, int timeout, final String password,
            final int database) {
        this.poolConfig = poolConfig;
        this.timeout = timeout;
        this.password = password;
        this.database = database;

        List<HostAndPort> masterList = initSentinels(sentinels, masters);
        initPool(masterList);
    }

    public void destroy() {
        for (MasterListener m : masterListeners) {
            m.shutdown();
        }

        super.destroy();
    }

    public List<HostAndPort> getCurrentHostMaster() {
        return currentHostMasters;
    }

    private void initPool(List<HostAndPort> masters) {
        if (!equals(currentHostMasters, masters)) {
            StringBuffer sb = new StringBuffer();
            for (HostAndPort master : masters) {
                sb.append(master.toString());
                sb.append(" ");
            }
            log.info("Created ShardedJedisPool to master at [" + sb.toString() + "]");
            List<JedisShardInfo> shardMasters = makeShardInfoList(masters);
            initPool(poolConfig, new ShardedJedisFactory(shardMasters, Hashing.MURMUR_HASH, null));
            currentHostMasters = masters;
        }
    }

    private boolean equals(List<HostAndPort> currentShardMasters, List<HostAndPort> shardMasters) {
        if (currentShardMasters != null && shardMasters != null) {
            if (currentShardMasters.size() == shardMasters.size()) {
                for (int i = 0; i < currentShardMasters.size(); i++) {
                    if (!currentShardMasters.get(i).equals(shardMasters.get(i)))
                        return false;
                }
                return true;
            }
        }
        return false;
    }

    private List<JedisShardInfo> makeShardInfoList(List<HostAndPort> masters) {
        List<JedisShardInfo> shardMasters = new ArrayList<JedisShardInfo>();
        for (HostAndPort master : masters) {
            JedisShardInfo jedisShardInfo = new JedisShardInfo(master.getHost(), master.getPort(), timeout);
            jedisShardInfo.setPassword(password);

            shardMasters.add(jedisShardInfo);
        }
        return shardMasters;
    }

    private List<HostAndPort> initSentinels(Set<String> sentinels, final List<String> masters) {

        Map<String, HostAndPort> masterMap = new HashMap<String, HostAndPort>();
        List<HostAndPort> shardMasters = new ArrayList<HostAndPort>();

        log.info("Trying to find all master from available Sentinels...");

        for (String masterName : masters) {
            HostAndPort master = null;
            boolean fetched = false;

            while (!fetched && sentinelRetry < MAX_RETRY_SENTINEL) {
                for (String sentinel : sentinels) {
                    final HostAndPort hap = toHostAndPort(Arrays.asList(sentinel.split(":")));

                    System.out.println("Connecting to Sentinel " + hap);

                    try {
                        Jedis jedis = new Jedis(hap.getHost(), hap.getPort());
                        master = masterMap.get(masterName);
                        if (master == null) {
                            List<String> hostAndPort = jedis.sentinelGetMasterAddrByName(masterName);
                            if (hostAndPort != null && hostAndPort.size() > 0) {
                                master = toHostAndPort(hostAndPort);
                                System.out.println("Found Redis master at " + master);
                                shardMasters.add(master);
                                masterMap.put(masterName, master);
                                fetched = true;
                                jedis.disconnect();
                                break;
                            }
                        }
                    } catch (JedisConnectionException e) {
                        log.warning("Cannot connect to sentinel running @ " + hap + ". Trying next one.");
                    }
                }

                if (null == master) {
                    try {
                        log.severe("All sentinels down, cannot determine where is " + masterName + " master is running... sleeping 1000ms, Will try again.");
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    fetched = false;
                    sentinelRetry++;
                }
            }

            // Try MAX_RETRY_SENTINEL times.
            if (!fetched && sentinelRetry >= MAX_RETRY_SENTINEL) {
                log.severe("All sentinels down and try " + MAX_RETRY_SENTINEL + " times, Abort.");
                throw new JedisConnectionException("Cannot connect all sentinels, Abort.");
            }
        }

        // All shards master must been accessed.
        if (masters.size() != 0 && masters.size() == shardMasters.size()) {

            log.info("Starting Sentinel listeners...");
            for (String sentinel : sentinels) {
                final HostAndPort hap = toHostAndPort(Arrays.asList(sentinel.split(":")));
                MasterListener masterListener = new MasterListener(masters, hap.getHost(), hap.getPort());
                masterListeners.add(masterListener);
                masterListener.start();
            }
        }

        return shardMasters;
    }

    private HostAndPort toHostAndPort(List<String> getMasterAddrByNameResult) {
        String host = getMasterAddrByNameResult.get(0);
        int port = Integer.parseInt(getMasterAddrByNameResult.get(1));

        return new HostAndPort(host, port);
    }

    /**
     * PoolableObjectFactory custom impl.
     */
    protected static class ShardedJedisFactory implements PooledObjectFactory<ShardedJedis> {
        private List<JedisShardInfo> shards;
        private Hashing algo;
        private Pattern keyTagPattern;

        public ShardedJedisFactory(List<JedisShardInfo> shards, Hashing algo, Pattern keyTagPattern) {
            this.shards = shards;
            this.algo = algo;
            this.keyTagPattern = keyTagPattern;
        }

        public PooledObject<ShardedJedis> makeObject() throws Exception {
            ShardedJedis jedis = new ShardedJedis(shards, algo, keyTagPattern);
            return new DefaultPooledObject<ShardedJedis>(jedis);
        }

        public void destroyObject(PooledObject<ShardedJedis> pooledShardedJedis) throws Exception {
            final ShardedJedis shardedJedis = pooledShardedJedis.getObject();
            for (Jedis jedis : shardedJedis.getAllShards()) {
                try {
                    try {
                        jedis.quit();
                    } catch (Exception e) {

                    }
                    jedis.disconnect();
                } catch (Exception e) {

                }
            }
        }

        public boolean validateObject(PooledObject<ShardedJedis> pooledShardedJedis) {
            try {
                ShardedJedis jedis = pooledShardedJedis.getObject();
                for (Jedis shard : jedis.getAllShards()) {
                    if (!shard.ping().equals("PONG")) {
                        return false;
                    }
                }
                return true;
            } catch (Exception ex) {
                return false;
            }
        }

        public void activateObject(PooledObject<ShardedJedis> p) throws Exception {

        }

        public void passivateObject(PooledObject<ShardedJedis> p) throws Exception {

        }
    }

    protected class JedisPubSubAdapter extends JedisPubSub {
        @Override
        public void onMessage(String channel, String message) {
        }

        @Override
        public void onPMessage(String pattern, String channel, String message) {
        }

        @Override
        public void onPSubscribe(String pattern, int subscribedChannels) {
        }

        @Override
        public void onPUnsubscribe(String pattern, int subscribedChannels) {
        }

        @Override
        public void onSubscribe(String channel, int subscribedChannels) {
        }

        @Override
        public void onUnsubscribe(String channel, int subscribedChannels) {
        }
    }

    protected class MasterListener extends Thread {

        protected List<String> masters;
        protected String host;
        protected int port;
        protected long subscribeRetryWaitTimeMillis = 5000;
        protected Jedis jedis;
        protected AtomicBoolean running = new AtomicBoolean(false);

        protected MasterListener() {
        }

        public MasterListener(List<String> masters, String host, int port) {
            this.masters = masters;
            this.host = host;
            this.port = port;
        }

        public MasterListener(List<String> masters, String host, int port, long subscribeRetryWaitTimeMillis) {
            this(masters, host, port);
            this.subscribeRetryWaitTimeMillis = subscribeRetryWaitTimeMillis;
        }

        public void run() {

            running.set(true);

            while (running.get()) {

                jedis = new Jedis(host, port);

                try {
                    jedis.subscribe(new JedisPubSubAdapter() {
                        @Override
                        public void onMessage(String channel, String message) {
                            System.out.println("Sentinel " + host + ":" + port + " published: " + message + ".");
//                            1) "message"
//                            2) "+switch-master"
//                            3) "shard1 192.168.77.135 6379 192.168.77.135 6378"
                            String[] switchMasterMsg = message.split(" ");

                            if (switchMasterMsg.length > 3) {

                                int index = masters.indexOf(switchMasterMsg[0]);
                                if (index >= 0) {
                                    HostAndPort newHostMaster = toHostAndPort(Arrays.asList(switchMasterMsg[3], switchMasterMsg[4]));
                                    List<HostAndPort> newHostMasters = new ArrayList<HostAndPort>();
                                    for (int i = 0; i < masters.size(); i++) {
                                        newHostMasters.add(null);
                                    }
                                    Collections.copy(newHostMasters, currentHostMasters);
                                    newHostMasters.set(index, newHostMaster);

                                    initPool(newHostMasters);
                                } else {
                                    StringBuffer sb = new StringBuffer();
                                    for (String masterName : masters) {
                                        sb.append(masterName);
                                        sb.append(",");
                                    }
                                    System.out.println("Ignoring message on +switch-master for master name " + switchMasterMsg[0] + ", our monitor master name are ["
                                            + sb + "]");
                                }

                            } else {
                                log.severe("Invalid message received on Sentinel " + host + ":" + port + " on channel +switch-master: " + message);
                            }
                        }
                    }, "+switch-master");

                } catch (JedisConnectionException e) {

                    if (running.get()) {
                        log.severe("Lost connection to Sentinel at " + host + ":" + port + ". Sleeping 5000ms and retrying.");
                        try {
                            Thread.sleep(subscribeRetryWaitTimeMillis);
                        } catch (InterruptedException e1) {
                            e1.printStackTrace();
                        }
                    } else {
                        System.out.println("Unsubscribing from Sentinel at " + host + ":" + port);
                    }
                }
            }
        }

        public void shutdown() {
            try {
                System.out.println("Shutting down listener on " + host + ":" + port);
                running.set(false);
                // This isn't good, the Jedis object is not thread safe
                jedis.disconnect();
            } catch (Exception e) {
                log.severe("Caught exception while shutting down: " + e.getMessage());
            }
        }
    }
}

测试类

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import junit.framework.TestCase;

import org.apache.commons.pool2.impl.GenericObjectPoolConfig;

import redis.ShardedJedisSentinelPool;
import redis.clients.jedis.ShardedJedis;
import redis.clients.jedis.exceptions.JedisConnectionException;

public class ShardedJedisSentinelPoolTest extends TestCase {

    public void testX() throws Exception {
        
        GenericObjectPoolConfig config = new GenericObjectPoolConfig();
        
        List<String> masters = new ArrayList<String>();
        masters.add("shard1");
        masters.add("shard2");
        Set<String> sentinels = new HashSet<String>();
        sentinels.add("192.168.77.135:26379");
        sentinels.add("192.168.77.135:26380");
        sentinels.add("192.168.77.135:26381");
    
        ShardedJedisSentinelPool pool = new ShardedJedisSentinelPool(masters, sentinels, config, 60000);
        
        ShardedJedis jedis = null;
        try {
            jedis = pool.getResource();
            System.out.println("Current master: " + pool.getCurrentHostMaster().toString());
            jedis.set("b","liangzhichao1");
            String value = jedis.get("b");
            System.out.println("b: " + value);
        } finally {
            if (jedis != null) pool.returnResource(jedis);
//            pool.destroy();
        }
        
        ShardedJedis j = null;
        for (int i = 0; i < 50; i++) {
            try {
                j = pool.getResource();
                j.set("KEY: " + i, "" + i);
                System.out.print(i);
                System.out.print(" ");
                Thread.sleep(500);
                pool.returnResource(j);
            } catch (JedisConnectionException e) {
                System.out.print("x");
                i--;
                Thread.sleep(1000);
            }
        }
    
        System.out.println("");
    
        for (int i = 0; i < 50; i++) {
            try {
                j = pool.getResource();
                assertEquals(j.get("KEY: " + i), "" + i);
                System.out.print(".");
                Thread.sleep(500);
                pool.returnResource(j);
            } catch (JedisConnectionException e) {
                System.out.print("x");
                i--;
                Thread.sleep(1000);
            }
        }

        pool.destroy();
    }
    
    public static void main(String[] args) throws Exception {
        new ShardedJedisSentinelPoolTest().testX();
    }
}

测试过程中，可以进入linux后台，终止掉6378的进程，查看主从切换情况

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原文地址：https://www.cnblogs.com/yangmengdx3/p/4708623.html