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DocumentationTencentDB for Redis®Operation GuideSentinel Mode
Sentinel Mode
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Last updated: 2024-11-05 10:15:53
Sentinel Mode
Last updated: 2024-11-05 10:15:53
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Overview

Sentinel is a standalone process that monitors the master and replica nodes in a Redis cluster. When the master node fails, Sentinel can elect a new master from the replica nodes to replace it automatically. This high-availability solution ensures that business operations run smoothly.
Note：
The Memcached Edition does not support Sentinel mode.

Sentinel Commands

TencentDB for Redis® 4.0 and later support the Sentinel mode by default. You can use the following Sentinel commands.

SENTINEL sentinels

This command lists the sentinels information of the monitored master.

Command format

SENTINEL sentinels <any name>

Sample code



SENTINEL get-master-addr-by-name

This command gets the IP address information of the master-name.

Command format

SENTINEL get-master-addr-by-name <any name>

Sample code



Connection Sample for the Sentinel Mode

Prerequisites

The Redis instance version is 4.0 or 5.0.
The database instance is in the Running status.
Get the private IPv4 address and port information for database connection in the Network Info section on the Instance Details page in the TencentDB for Redis® console. For detailed directions, see Viewing Instance Information.
Get the account and password for database access. For detailed directions, see Managing Account.
Download and install Jedis. The latest version is recommended.

Connection sample

The following sample code takes Jedis 3.6.0 as an example. The latest version is recommended.
The Jedis version is 3.6.0 or later.
The Lettuce version is 5.3.0.RELEASE or later.
The Spring Data Redis version is 2.5.1 or later, for which the spring.redis.sentinel.password parameter should be configured.
You need to modify the parameters based on the comments, including IP, port, account, and password for database access.

Connection via Java

package com.example.demo;

import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import redis.clients.jedis.JedisSentinelPool;

import java.util.HashSet;
import java.util.Set;

public class Main {
    public static void main(String[] args) {
        String masterName = "test";
        Set<String> sentinels = new HashSet<>();
        // You need to configure the database instance's private IPv4 address and port
        sentinels.add("XX.XX.XX.XX:6379");
        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
        String dbPassword = "root:xxx";//Replace this with your database access password
        String sentinelPassword = "root:xxx";//Replace this with your database access password

        JedisSentinelPool jedisSentinelPool =
            new JedisSentinelPool(masterName, sentinels, poolConfig,
                2000, 2000, dbPassword,
                0, null, 2000, 2000,
                sentinelPassword, null);
        System.out.println("jedisSentinelPool.getResource().ping() = " + jedisSentinelPool.getResource().ping());
        jedisSentinelPool.close();
    }
}

Connection via the Spring Data framework

package com.example.demo;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.RedisSentinelConfiguration;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import redis.clients.jedis.JedisPoolConfig;

@SpringBootApplication

public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

@Configuration
class RedisConfig {
    @Bean
    @Qualifier("jedisConnectionFactory")
    public JedisConnectionFactory connectionFactory() {
        RedisSentinelConfiguration sentinelConfig = new RedisSentinelConfiguration()
            .master("test")
            .sentinel("XX.XX.XX.XX", 6379);//Replace this with the private IPv4 address and port of your database instance
        sentinelConfig.setPassword(RedisPassword.of("xxx"));//Replace this with your database access password
        sentinelConfig.setSentinelPassword(RedisPassword.of("xxx"));//Replace this with your database access password
        JedisPoolConfig poolConfig = new JedisPoolConfig();
        JedisConnectionFactory connectionFactory = new JedisConnectionFactory(sentinelConfig, poolConfig);
        connectionFactory.afterPropertiesSet();
        return connectionFactory;
    }

    @Bean
    @ConditionalOnBean(JedisConnectionFactory.class)
    public RedisTemplate<String, String> redisTemplate(@Qualifier("jedisConnectionFactory") JedisConnectionFactory factory) {
        RedisTemplate<String, String> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        template.afterPropertiesSet();
        //test
        template.opsForValue().set("test", "test1");
        System.out.println("template.opsForValue().get(\"test\") = " + template.opsForValue().get("test"));
        return template;
    }

}
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