Redis Sentinel安装与部署,实现redis的高可用

前言

  对于生产环境,高可用是避免不了要面对的问题,无论什么环境、服务,只要用于生产,就需要满足高可用;此文针对的是redis的高可用。

  接下来会有系列文章,该系列是对spring-session实现分布式集群session的共享的完整阐述,同时也引伸出缓存的实现;而此篇是该系列的第一篇。

  github地址:https://github.com/youzhibing/redis

环境准备

  redis版本:redis-3.0.0

  linux:centos6.7

  ip:192.168.11.202, 一台服务器上搭建搭建全部redis实例,包括数据节点实例以及哨兵(sentinel)实例

  客户端jedis,基于spring-boot

redis主从复制

  搭建一主二从的主从环境

  1、redis安装

    安装很简单,网上资料很多,redis官网也有说明;主要就是3步:解压,make,make install

  2、数据节点配置文件

    redis解压后,redis home目录下有redis配置的样例文件,我们不直接在此文件上就行修改,在redis home目录下新建文件夹master_slave,将配置文件都放于此目录下

    master配置文件:redis-6379.conf

port 6379
bind 192.168.11.202
requirepass "myredis"
daemonize yes
logfile "6379.log"
dbfilename "dump-6379.rdb"
dir "/opt/soft/redis/data"

#如若master设置了认证密码,那么所有redis数据节点都配置上masterauth属性
masterauth "myredis"

    slave-1配置文件:redis-6380.conf

port 6380
bind 192.168.11.202
requirepass "myredis"
daemonize yes
logfile "6380.log"
dbfilename "dump-6380.rdb"
dir "/opt/soft/redis/data"

#如若master设置了认证密码,那么所有redis数据节点都配置上masterauth属性
masterauth "myredis"
slaveof 192.168.11.202 6379

    slave-2配置文件:redis-6381.conf

port 6381
bind 192.168.11.202
requirepass "myredis"
daemonize yes
logfile "6381.log"
dbfilename "dump-6381.rdb"
dir "/opt/soft/redis/data"

#如若master设置了认证密码,那么所有redis数据节点都配置上masterauth属性
masterauth "myredis"
slaveof 192.168.11.202 6379

  3、节点启动

    如下相关路径需要根据自己的情况进行改动,可能和我的不一样

[root@slave1 master_slave]# cd /opt/redis-3.0.0/master_slave/
[root@slave1 master_slave]# ./../src/redis-server redis-6379.conf 
[root@slave1 master_slave]# ./../src/redis-server redis-6380.conf 
[root@slave1 master_slave]# ./../src/redis-server redis-6381.conf

    确认主从关系

[root@slave1 master_slave]# ./../src/redis-cli -h 192.168.11.202 -p 6379 -a myredis info replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.11.202,port=6380,state=online,offset=393,lag=0
slave1:ip=192.168.11.202,port=6381,state=online,offset=393,lag=0
master_repl_offset:393
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:392

    还可以从从节点视角来看:[root@slave1 master_slave]# ./../src/redis-cli -h 192.168.11.202 -p 6380 -a myredis info replication

  如若进行顺利,按如上配置,一主二从环境搭建完毕

  4、从节点作用

    主要两个作用:1、作为主节点的一个备份,一旦主节点出现故障,从节点可以作为后备"顶"上来,并且保证数据尽量不丢失(主从复制是最终一致性);2、从节点可以拓展主节点的能力,一旦主节点不能支撑大并发的读操作,从节点可以在一定程度上帮助主节点分担读压力

  5、主从复制问题

    1、一旦主节点出现故障,需要手动将一个从节点晋升为主节点,同时需要修改应用方的主节点地址,还需要命令其他从节点去复制新的主节点,整个过程需要人工干预

    2、主节点的写能力受到单机的限制

    3、主节点的存储能力受到单机的限制

redis sentinel部署

  此片主要讲通过sentinel解决上述问题1,问题2、3则在下篇博客进行说明

  1、3个sentinel节点的配置文件基本一致,区别的只是端口

    sentinel-26379.conf

port 26379
daemonize yes
logfile "26379.log"
dir "/opt/soft/redis/data"
sentinel monitor mymaster 192.168.11.202 6380 2
#redis数据master节点设置了认证,则需要如下配置
sentinel auth-pass mymaster myredis
sentinel down-after-milliseconds mymaster 30000
sentinel parallel-syncs mymaster 1
sentinel failover-timeout mymaster 180000

    sentinel-26380.conf

port 26380
daemonize yes
logfile "26379.log"
dir "/opt/soft/redis/data"
sentinel monitor mymaster 192.168.11.202 6380 2
#redis数据master节点设置了认证,则需要如下配置
sentinel auth-pass mymaster myredis
sentinel down-after-milliseconds mymaster 30000
sentinel parallel-syncs mymaster 1
sentinel failover-timeout mymaster 180000

    sentinel-26381.conf

port 26381
daemonize yes
logfile "26379.log"
dir "/opt/soft/redis/data"
sentinel monitor mymaster 192.168.11.202 6380 2
#redis数据master节点设置了认证,则需要如下配置
sentinel auth-pass mymaster myredis
sentinel down-after-milliseconds mymaster 30000
sentinel parallel-syncs mymaster 1
sentinel failover-timeout mymaster 180000

  2、启动sentinel

[root@slave1 master_slave]# ./../src/redis-sentinel sentinel-26379.conf 
[root@slave1 master_slave]# ./../src/redis-sentinel sentinel-26380.conf 
[root@slave1 master_slave]# ./../src/redis-sentinel sentinel-26381.conf

  3、sentinel确认

[root@slave1 master_slave]# ./../src/redis-cli -h 192.168.11.202 -p 26379 info Sentinel
# Sentinel
sentinel_masters:1
sentinel_tilt:0
sentinel_running_scripts:0
sentinel_scripts_queue_length:0
master0:name=mymaster,status=ok,address=192.168.11.202:6379,slaves=2,sentinels=3

  Redis  Sentinel 最终拓扑结构

 

  4、高可用测试

    手动停掉6379实例或者kill掉6379实例

[root@slave1 master_slave]# ./../src/redis-cli -h 192.168.11.202 -p 6379 -a myredis
192.168.11.202:6379> shutdown

    查看26379.log

    master节点已经自动切换到192.168.11.202:6380了,重启6379,6379则是6378的从节点了。

[root@slave1 master_slave]# ./../src/redis-cli -h 192.168.11.202 -p 6380 -a myredis
192.168.11.202:6380> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=192.168.11.202,port=6381,state=online,offset=80802,lag=1
slave1:ip=192.168.11.202,port=6379,state=online,offset=80802,lag=1
master_repl_offset:80945
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:2
repl_backlog_histlen:80944 

客户端(Jedis)连接

  基于spring-boot开发,spring-boot-test测试, 这两者本文不做说明,网上资料很多,不熟悉的自行去补充; 工程结构如下图

  pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.lee</groupId>
    <artifactId>redis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>redis</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        
        <!-- 日志过滤器 -->
        <dependency>
            <groupId>org.codehaus.janino</groupId>
            <artifactId>janino</artifactId>
        </dependency>
    </dependencies>
</project>
View Code

  redis-sentinel.properties

redis.masterName=mymaster
redis.sentinels=192.168.11.202:26379,192.168.11.202:26380,192.168.11.202:26381
redis.timeout=10000
#连接master需要用到的密码,如果redis数据节点开启了连接认证
redis.password=myredis

# 连接池
# 连接池最大连接数(使用负值表示没有限制)
redis.pool.maxActive=150
# 连接池中的最大空闲连接
redis.pool.maxIdle=10
# 连接池中的最小空闲连接
redis.pool.minIdle=1
# 获取连接时的最大等待毫秒数,小于零:阻塞不确定的时间,默认-1
redis.pool.maxWaitMillis=3000
# 每次释放连接的最大数目
redis.pool.numTestsPerEvictionRun=50
# 释放连接的扫描间隔(毫秒)
redis.pool.timeBetweenEvictionRunsMillis=3000
# 连接最小空闲时间(毫秒)
redis.pool.minEvictableIdleTimeMillis=1800000
# 连接空闲多久后释放, 当空闲时间>该值 且 空闲连接>最大空闲连接数 时直接释放(毫秒)
redis.pool.softMinEvictableIdleTimeMillis=10000
# 在获取连接的时候检查有效性, 默认false
redis.pool.testOnBorrow=true
# 在空闲时检查有效性, 默认false
redis.pool.testWhileIdle=true
# 在归还给pool时,是否提前进行validate操作
redis.pool.testOnReturn=true
# 连接耗尽时是否阻塞, false报异常,ture阻塞直到超时, 默认true
redis.pool.blockWhenExhausted=true
View Code

  RedisConfig.java

package com.lee.redis.config;

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

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

import redis.clients.jedis.JedisPoolConfig;
import redis.clients.jedis.JedisSentinelPool;

@Configuration
@PropertySource("redis/redis-sentinel.properties")
public class RedisConfig {
    private static final Logger LOGGER = LoggerFactory.getLogger(RedisConfig.class);
    
    @Value("${redis.masterName}")
    private String masterName;
    @Value("${redis.sentinels}")
    private String sentinels;
    @Value("${redis.timeout}")
    private int timeout;
    @Value("${redis.password}")
    private String password;
    
    @Value("${redis.pool.maxActive}")
    private int maxTotal;

    @Value("${redis.pool.maxIdle}")
    private int maxIdle;

    @Value("${redis.pool.minIdle}")
    private int minIdle;

    @Value("${redis.pool.maxWaitMillis}")
    private long maxWaitMillis;

    @Value("${redis.pool.numTestsPerEvictionRun}")
    private int numTestsPerEvictionRun;

    @Value("${redis.pool.timeBetweenEvictionRunsMillis}")
    private long timeBetweenEvictionRunsMillis;

    @Value("${redis.pool.minEvictableIdleTimeMillis}")
    private long minEvictableIdleTimeMillis;

    @Value("${redis.pool.softMinEvictableIdleTimeMillis}")
    private long softMinEvictableIdleTimeMillis;

    @Value("${redis.pool.testOnBorrow}")
    private boolean testOnBorrow;

    @Value("${redis.pool.testWhileIdle}")
    private boolean testWhileIdle;

    @Value("${redis.pool.testOnReturn}")
    private boolean testOnReturn;

    @Value("${redis.pool.blockWhenExhausted}")
    private boolean blockWhenExhausted;
    
    @SuppressWarnings({ "unchecked", "rawtypes" })
    @Bean
    public JedisSentinelPool jedisSentinelPool(JedisPoolConfig poolConfig) {
        LOGGER.info("sentinel set : {}", sentinels);
        Set sentinelSet = new HashSet(Arrays.asList(sentinels.split(",")));
        JedisSentinelPool jedisPool = new JedisSentinelPool(masterName, sentinelSet, poolConfig, timeout, password);
        return jedisPool;
    }
    
    @Bean
    public JedisPoolConfig jedisPoolConfig() {
        JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
        jedisPoolConfig.setMaxTotal(maxTotal);
        jedisPoolConfig.setMaxIdle(maxIdle);
        jedisPoolConfig.setMinIdle(minIdle);
        jedisPoolConfig.setMaxWaitMillis(maxWaitMillis);
        jedisPoolConfig.setNumTestsPerEvictionRun(numTestsPerEvictionRun);
        jedisPoolConfig
                .setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        jedisPoolConfig
                .setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        jedisPoolConfig
                .setSoftMinEvictableIdleTimeMillis(softMinEvictableIdleTimeMillis);
        jedisPoolConfig.setTestOnBorrow(testOnBorrow);
        jedisPoolConfig.setTestWhileIdle(testWhileIdle);
        jedisPoolConfig.setTestOnReturn(testOnReturn);
        jedisPoolConfig.setBlockWhenExhausted(blockWhenExhausted);

        return jedisPoolConfig;
    }
}
View Code

  Application.java

package com.lee.redis;

import org.springframework.boot.Banner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application {

    public static void main(String[] args) {
        
        SpringApplication app = new SpringApplication(Application.class);
        app.setBannerMode(Banner.Mode.OFF);            // 是否打印banner
        // app.setApplicationContextClass();        // 指定spring应用上下文启动类
        app.setWebEnvironment(false);
        app.run(args);
    }
}
View Code

  RedisTest.java

package com.lee.redis;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisSentinelPool;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = Application.class)
public class RedisTest {

    private static final Logger LOGGER = LoggerFactory.getLogger(RedisTest.class);
    
    @Autowired
    private JedisSentinelPool sentinelPool;
    
    @Test
    public void getNameTest() {
        Jedis jedis = null;
        try {
            jedis = sentinelPool.getResource();
            String name = jedis.get("name");
            System.out.println("name is " + name);
        } catch(Exception e) {
            LOGGER.error(e.getMessage(), e);
        } finally {
            if (jedis != null) {
                jedis.close();
            }
        }
        
    }
    
}
View Code

  更多详情请上我的github

  运行RedisTest.java的getNameTest方法(name属性已经在redis中设置,没设置的需要提前设置),得到结果:

注意点

  1、有人可能会有这样的疑问:为什么通过sentinel来获取redis的连接,而不是直接连接master来获取redis连接呢?

    试想一下,客户端直接通过master节点获取redis连接,如果master节点挂掉了,虽然Redis Sentinel可以完成故障转移,但是客户端无法获取这个变化,那么客户端就无法获取redis连接了;

    最了解master节点信息的就是Sentinel节点集合,所以通过sentinel来获取redis连接就能满足高可用的要求了。

  2、redis master的故障转移不影响客户端连接代码, 但是转移期间内,通过sentinel是获取不到主节点的连接的, 因为转移期间内master节点还没被选举出来;

参考

  《Redis开发与运维》

  http://www.redis.cn/topics/sentinel.html

posted @ 2018-02-24 20:40 youzhibing2904 阅读(...) 评论(...) 编辑 收藏