Htykuut

I have setup 3 Redis Server and 3 Redis Sentinel instances in my localhost. The servers are running at:

127.0.0.1:6379 // Master

127.0.0.1:6380 // Slave

127.0.0.1:6381 // Slave

and the sentinels are running at:

127.0.0.1:5000

127.0.0.1:5001

127.0.0.1:5002

I have a (Java) client that tries to connect to one of the sentinels and set the keys in redis server:

// import statements



public class RedisPush {



    private static final String MASTER_NAME = "mymaster";

    private static final String PASSWORD = "foobared";

    private static final Set sentinels;

    static {

        sentinels = new HashSet();

        sentinels.add("127.0.0.1:5000");

        sentinels.add("127.0.0.1:5001");

        sentinels.add("127.0.0.1:5002");

    }



    public static void pushToRedis() {



        Jedis jedis = null;



        try {

            JedisSentinelPool pool = new JedisSentinelPool(MASTER_NAME, sentinels);

            System.out.println("Fetching connection from pool.");

            jedis = pool.getResource();

            jedis.auth(PASSWORD);

            Socket socket = jedis.getClient().getSocket();



            System.out.println("Connected to " + socket.getRemoteSocketAddress());

            int i = 0;

            while (true) {

                jedis.set("sentinel_key" + i, "value" + i);

                System.out.println(i);

                i++;

                Thread.sleep(1000);

            }



        } catch (Exception e) {

            e.printStackTrace();

        }

        finally {

            if(jedis != null)

                jedis.close();

        }



    }



    public static void main(String args) throws Exception {



        while(true) {



            pushToRedis();

            Thread.sleep(1000);

        }

    }

}

Initially, my sentinel configuration is as follows (for example, the first sentinel running on port 5000):

bind 127.0.0.1

port 5000

sentinel monitor mymaster 127.0.0.1 6379 2

sentinel down-after-milliseconds mymaster 5000

sentinel failover-timeout mymaster 60000

sentinel auth-pass mymaster foobared

If I try to run my (Java) client, I get the following error:

Nov 23, 2018 1:52:57 AM redis.clients.jedis.JedisSentinelPool initSentinels

INFO: Trying to find master from available Sentinels...

Nov 23, 2018 1:52:57 AM redis.clients.jedis.JedisSentinelPool initSentinels

WARNING: Cannot get master address from sentinel running @ 192.168.0.102:5001. Reason: redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused (Connection refused). Trying next one.

Nov 23, 2018 1:52:57 AM redis.clients.jedis.JedisSentinelPool initSentinels

WARNING: Cannot get master address from sentinel running @ 192.168.0.102:5000. Reason: redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused (Connection refused). Trying next one.

Nov 23, 2018 1:52:57 AM redis.clients.jedis.JedisSentinelPool initSentinels

WARNING: Cannot get master address from sentinel running @ 192.168.0.102:5002. Reason: redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused (Connection refused). Trying next one.

redis.clients.jedis.exceptions.JedisConnectionException: All sentinels down, cannot determine where is mymaster master is running...

    at redis.clients.jedis.JedisSentinelPool.initSentinels(JedisSentinelPool.java:180)

    at redis.clients.jedis.JedisSentinelPool.<init>(JedisSentinelPool.java:95)

    at redis.clients.jedis.JedisSentinelPool.<init>(JedisSentinelPool.java:82)

    at redis.clients.jedis.JedisSentinelPool.<init>(JedisSentinelPool.java:70)

    at redis.clients.jedis.JedisSentinelPool.<init>(JedisSentinelPool.java:44)

    at RedisPush.pushToRedis(RedisPush.java:29)

    at RedisPush.main(RedisPush.java:61)

However, if I change my sentinel configuration script to the one below:

# bind 127.0.0.1

port 5000

protected-mode no

sentinel monitor mymaster 127.0.0.1 6379 2

sentinel down-after-milliseconds mymaster 5000

sentinel failover-timeout mymaster 60000

sentinel auth-pass mymaster foobared

the client works perfectly. I don't understand why.

AFAIK, if requirepass is not set in sentinel.conf file AND bind is commented in sentinel.conf file, ONLY then protected-mode will be yes to avoid any client connecting to the sentinel apart from localhost. In my first sentinel configuration, I had the bind command but still it didn't work.

Why does commenting out bind and explicitly setting protected-mode to no works?

P.S. I also tried having both bind 127.0.0.1 and protected-mode no but even that didn't work.