redis配置master－slave模式
由于云服务器存在闪断现象，项目线上会存在基于redis的功能在闪断时段内出现异常，所以redis需要做master－slave模式。直接上代码：
原单机redis，RedisConnectionFactory设置代码
```
@Bean
public RedisConnectionFactory jedisConnectionFactory(){
JedisPoolConfig poolConfig=new JedisPoolConfig();
poolConfig.setMaxIdle(5);
poolConfig.setMinIdle(1);
poolConfig.setTestOnBorrow(true);
poolConfig.setTestOnReturn(true);
poolConfig.setTestWhileIdle(true);
poolConfig.setNumTestsPerEvictionRun(10);
poolConfig.setTimeBetweenEvictionRunsMillis(60000);
JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory(poolConfig);
//单机redis的host、port设置
jedisConnectionFactory.setHostName(redishost);
jedisConnectionFactory.setPort(redisport);
jedisConnectionFactory.setDatabase(0);
return jedisConnectionFactory;
}
```
哨兵节点设置代码
```
@Bean
public RedisConnectionFactory jedisConnectionFactory(){
JedisPoolConfig poolConfig=new JedisPoolConfig();
poolConfig.setMaxIdle(5);
poolConfig.setMinIdle(1);
poolConfig.setTestOnBorrow(true);
poolConfig.setTestOnReturn(true);
poolConfig.setTestWhileIdle(true);
poolConfig.setNumTestsPerEvictionRun(10);
poolConfig.setTimeBetweenEvictionRunsMillis(60000);
//哨兵节点host、port设置，可设置多个哨兵，只需要链式新增 .sentinel(sentinelhost, sentinelport)
RedisSentinelConfiguration sentinelConfig = new RedisSentinelConfiguration() .master("mymaster")
.sentinel(sentinelhost, sentinelport);
JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory(sentinelConfig,poolConfig);
return jedisConnectionFactory;
}
```
由此，在master节点down了的时候，slave节点会自动升级到master。然后我们的服务会自动新建redis连接池到新的master节点。
```
2016-07-29 10:42:28,525 [MasterListener-mymaster-[10.10.180.37:26379]] INFO redis.clients.jedis.JedisSentinelPool - Created JedisPool to master at 10.10.129.188:6379
```
当哨兵节点down了的时候，服务日志会提示Lost connection to Sentinel,此时redis连接池不会断开，可继续使用，不影响业务，但是这时当master失去响应时就不会自动切换连接池了。为了避免这种情况可以配置多个哨兵（sentinel）节点，也可以通过sentinel配置文件的方式，当哨兵节点down了之后，通知运维同学。
```
2016-07-29 10:50:36,820 [MasterListener-mymaster-[10.10.180.37:26379]] ERROR redis.clients.jedis.JedisSentinelPool - Lost connection to Sentinel at 10.10.180.37:26379. Sleeping 5000ms and retrying.
2016-07-29 10:50:41,821 [MasterListener-mymaster-[10.10.180.37:26379]] ERROR redis.clients.jedis.JedisSentinelPool - Lost connection to Sentinel at 10.10.180.37:26379. Sleeping 5000ms and retrying.
2016-07-29 10:50:46,823 [MasterListener-mymaster-[10.10.180.37:26379]] ERROR redis.clients.jedis.JedisSentinelPool - Lost connection to Sentinel at 10.10.180.37:26379. Sleeping 5000ms and retrying.
2016-07-29 10:50:51,825 [MasterListener-mymaster-[10.10.180.37:26379]] ERROR redis.clients.jedis.JedisSentinelPool - Lost connection to Sentinel at 10.10.180.37:26379. Sleeping 5000ms and retrying.
2016-07-29 10:50:56,826 [MasterListener-mymaster-[10.10.180.37:26379]] ERROR redis.clients.jedis.JedisSentinelPool - Lost connection to Sentinel at 10.10.180.37:26379. Sleeping 5000ms and retrying.
