Use the Sentinel-compatible mode to connect to an instance

Tair (Redis OSS-compatible) uses the high availability (HA) component developed by Alibaba Cloud instead of Redis Sentinel. To improve instance compatibility and reduce code changes, Tair (Redis OSS-compatible) provides the Sentinel-compatible mode. After you enable the mode, you can connect to a Tair or Redis Open-Source Edition instance in the same way as you connect to Redis Sentinel.

Prerequisites

• The engine version of the instance is Redis 4.0 or later.

• The instance is deployed in a virtual private cloud (VPC).

  Note

  If the instance runs in the classic network, switch the network type of the instance to VPC. For more information, see Switch the network type from classic network to VPC.

• The internal IP address of your Elastic Compute Service (ECS) instance or the public IP address of your on-premises host is added to an IP address whitelist of the instance. For more information, see Configure whitelists.

Procedure

1. Log on to the console and go to the Instances page. In the top navigation bar, select the region in which the instance that you want to manage resides. Then, find the instance and click the instance ID.

2. In the left-side navigation pane of the Instance Information page, click Parameter Settings.

3. Enable the Sentinel-compatible mode for the instance by modifying the corresponding parameter based on the instance architecture. For more information, see Configure instance parameters.

   • If the instance is a read/write splitting instance or a cluster instance in proxy mode, set the sentinel_compat_enable parameter to 1.

   • If the instance is a standard instance, set the #no_loose_sentinel-enabled parameter to yes.

   Note

   • You can view the instance architecture on the instance details page.

   • Cluster instances in direct connection mode use open source Redis Cluster for load balancing, eliminating the need for the Sentinel component. Additionally, Sentinel parameters cannot be configured in this mode.

4. (Optional) After you enable the Sentinel-compatible mode for the instance, connect to the instance and run the SENTINEL sentinels test command. If the command execution is successful, the Redis Sentinel-compatible mode is enabled for the instance.

   The Sentinel-compatible mode does not provide additional endpoints. You can use the original endpoint, such as r-********.redis.rds.aliyuncs.com:6379 to connect to the instance.

   Note

   • To enable password-free access for the SENTINEL command, you can set the #no_loose_sentinel-password-free-access parameter to yes. This allows the use of the SUBSCRIBE and SENTINEL commands to subscribe to and listen for the +switch-master channel without requiring a password.

   • If you want to allow additional commands to be accessed without using a password, you can use the #no_loose_sentinel-password-free-commands parameter to specify the commands after you set the #no_loose_sentinel-password-free-access parameter to yes.

Connect to an instance in Sentinel-compatible mode

After you enable the Sentinel-compatible mode, you can use one of the following methods to connect to the instance: If you enable password-free access for the instance, you can connect to the instance in Sentinel-compatible mode. Otherwise, you must configure authentication information when you connect to the instance.

    @Bean
    public JedisConnectionFactory connectionFactory() {
        RedisSentinelConfiguration sentinelConfig = new RedisSentinelConfiguration()
                .master("testmaster")
                .sentinel("r-bp10noxlhcoim2****.redis.rds.aliyuncs.com", 6379);
        JedisPoolConfig poolConfig = new JedisPoolConfig();
        ...
        JedisConnectionFactory connectionFactory = new JedisConnectionFactory(sentinelConfig, poolConfig);
        return connectionFactory;
    }

from redis.sentinel import Sentinel
SENTINEL_HOST = "r-bp10noxlhcoim2****.redis.rds.aliyuncs.com"
SENTINEL_PORT = 6379
SENTINEL_MASTER_NAME = "testmaster"

sentinel = Sentinel([(SENTINEL_HOST, SENTINEL_PORT)])
r = sentinel.master_for(SENTINEL_MASTER_NAME, db=0)
r.set('foo', 'bar')
print(r.get('foo'))

        String masterName = "any-name";
        Set<String> sentinels = new HashSet<>();
        sentinels.add("r-bp10noxlhcoim2****.redis.rds.aliyuncs.com:6379");
        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
        String dbPassword = "testaccount:Rp829dlwa";
        String sentinelPassword = "testaccount:Rp829dlwa";

        JedisSentinelPool jedisSentinelPool =
                new JedisSentinelPool(masterName, sentinels, poolConfig,
                        2000, 2000, dbPassword,
                        0, null, 2000, 2000,
                        sentinelPassword, null);

from redis.sentinel import Sentinel
SENTINEL_HOST = "r-bp10noxlhcoim2****.rds.aliyuncs.com"
SENTINEL_PORT = 6379
SENTINEL_MASTER_NAME = "redis_master"  # Note: This name cannot be changed.
SENTINEL_REDIS_PWD = "testaccount:Rp829dlwa"

conf = {
    'password': SENTINEL_REDIS_PWD,
}

sentinel = Sentinel([(SENTINEL_HOST, SENTINEL_PORT)], sentinel_kwargs=conf)
r = sentinel.master_for(SENTINEL_MASTER_NAME, db=0, **conf)
r.set('foo', 'bar')
print(r.get('foo'))

FAQ

• What do I do if the NOAUTH Authentication required error message appears when I switch from the native Redis Sentinel mode to the Sentinel-compatible mode?

  You can set the #no_loose_sentinel-password-free-access parameter to yes to connect to the instance in Sentinel-compatible mode over a VPC without enabling password-free access.

  If the engine version of the instance is earlier than Redis 6.0, update your client, modify the code to add a password for Sentinel authentication, and then try again. For more information, see Connect to an instance in Sentinel-compatible mode by using a password.