Redis哨兵架构

sentinel哨兵是特殊的redis服务，不提供读写服务，主要用来监控redis实例节点。

在哨兵架构下client端第一次从哨兵找出redis的主节点，后继的读写操作直接访问redis的主节点，不会每次都通过sentinel代理访问redis的主节点，当redis的主节点发生了变化，哨兵会第一时间感知到，并且将redis的主节点通知给client端（redis的client端一般都实现了订阅功能，订阅sentinel发布的节点变动消息）。

Redis集群搭建

Redis主节点配置

创建主节点目录（/opt/redis-master），复制redis.conf到该目录下，redis.conf配置项修改

#后台启动
daemonize yes
#关闭保护模式，开启的话，只有本机才可以访问redis
protected-mode no  
# 需要注释掉bind
#bind 127.0.0.1（bind绑定的是自己机器网卡的ip，如果有多块网卡可以配多个ip，代表允许客户端通过机器的哪些网卡ip去访问，内网一般可以不配置bind，注释掉即可）
pidfile /var/run/redis_6379.pid
logfile "6379.log"

启动Redis主节点

/usr/local/redis-6.2.14/src/redis-server redis.conf

Redis从节点1配置

创建从节点目录（/opt/redis-slave-1），复制redis.conf到该目录下，redis.conf配置项修改

#后台启动
daemonize yes
#关闭保护模式，开启的话，只有本机才可以访问redis
protected-mode no  
# 需要注释掉bind
#bind 127.0.0.1（bind绑定的是自己机器网卡的ip，如果有多块网卡可以配多个ip，代表允许客户端通过机器的哪些网卡ip去访问，内网一般可以不配置bind，注释掉即可）
port 6380
pidfile /var/run/redis_6380.pid  # 把pid进程号写入pidfile配置的文件
logfile "6380.log"

#配置主从复制
replicaof 192.168.56.200 6379   # 从本机6379的redis实例复制数据，Redis 5.0之前使用slaveof
replica-read-only yes  # 配置从节点只读

启动Redis从节点

/usr/local/redis-6.2.14/src/redis-server redis.conf

Redis从节点2配置

创建从节点目录（/opt/redis-slave-2），复制redis.conf到该目录下，redis.conf配置项修改

#后台启动
daemonize yes
#关闭保护模式，开启的话，只有本机才可以访问redis
protected-mode no  
# 需要注释掉bind
#bind 127.0.0.1（bind绑定的是自己机器网卡的ip，如果有多块网卡可以配多个ip，代表允许客户端通过机器的哪些网卡ip去访问，内网一般可以不配置bind，注释掉即可）
port 6381
pidfile /var/run/redis_6381.pid  # 把pid进程号写入pidfile配置的文件
logfile "6380.log"

#配置主从复制
replicaof 192.168.56.200 6379   # 从本机6379的redis实例复制数据，Redis 5.0之前使用slaveof
replica-read-only yes  # 配置从节点只读

启动Redis从节点

/usr/local/redis-6.2.14/src/redis-server redis.conf

哨兵集群搭建

创建sentinel集群目录（/opt/redis-sentinel-1、/opt/redis-sentinel-2、/opt/redis-sentinel-3），分配拷贝sentinel.conf文件到这三个文件里。

redis-sentinel-1

创建data文件目录，修改sentinel-1 的sentinel.conf配置文件

# port <sentinel-port>
# The port that this sentinel instance will run on
port 26379
# By default Redis Sentinel does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis-sentinel.pid when
# daemonized.
daemonize yes
# When running daemonized, Redis Sentinel writes a pid file in
# /var/run/redis-sentinel.pid by default. You can specify a custom pid file
# location here.
pidfile ./redis-sentinel-26379.pid
# Specify the log file name. Also the empty string can be used to force
# Sentinel to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile "26379.log"
# dir <working-directory>
# Every long running process should have a well-defined working directory.
# For Redis Sentinel to chdir to /tmp at startup is the simplest thing
# for the process to don't interfere with administrative tasks such as
# unmounting filesystems.
dir "/opt/redis-sentinel-1/data"
# Note: master name should not include special characters or spaces.
# The valid charset is A-z 0-9 and the three characters ".-_".
# quorum是一个数字，指明当有多少个sentinel认为一个master失效时(值一般为：sentinel总数/2 + 1)，master才算真正失效
sentinel monitor mymaster 192.168.56.200 6379 2 # mymaster这个名字随便取，客户端访问时会用到

启动sentinel哨兵实例

/usr/local/redis-6.2.14/src/redis-sentinel sentinel.conf

查看sentinel的info信息

/usr/local/redis-6.2.14/src/redis-cli -p 26379 
127.0.0.1:26379> info

redis-sentinel-2

创建data文件目录，修改sentinel-1 的sentinel.conf配置文件

# port <sentinel-port>
# The port that this sentinel instance will run on
port 26380
# By default Redis Sentinel does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis-sentinel.pid when
# daemonized.
daemonize yes
# When running daemonized, Redis Sentinel writes a pid file in
# /var/run/redis-sentinel.pid by default. You can specify a custom pid file
# location here.
pidfile ./redis-sentinel-26380.pid
# Specify the log file name. Also the empty string can be used to force
# Sentinel to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile "26380.log"
# dir <working-directory>
# Every long running process should have a well-defined working directory.
# For Redis Sentinel to chdir to /tmp at startup is the simplest thing
# for the process to don't interfere with administrative tasks such as
# unmounting filesystems.
dir "/opt/redis-sentinel-2/data"
# Note: master name should not include special characters or spaces.
# The valid charset is A-z 0-9 and the three characters ".-_".
# quorum是一个数字，指明当有多少个sentinel认为一个master失效时(值一般为：sentinel总数/2 + 1)，master才算真正失效
sentinel monitor mymaster 192.168.56.200 6379 2 # mymaster这个名字随便取，客户端访问时会用到

启动sentinel哨兵实例

/usr/local/redis-6.2.14/src/redis-sentine2 sentinel.conf

查看sentinel的info信息

/usr/local/redis-6.2.14/src/redis-cli -p 26379 
127.0.0.1:26379> info

redis-sentinel-3

创建data文件目录，修改sentinel-1 的sentinel.conf配置文件

# port <sentinel-port>
# The port that this sentinel instance will run on
port 26381
# By default Redis Sentinel does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis-sentinel.pid when
# daemonized.
daemonize yes
# When running daemonized, Redis Sentinel writes a pid file in
# /var/run/redis-sentinel.pid by default. You can specify a custom pid file
# location here.
pidfile ./redis-sentinel-26381.pid
# Specify the log file name. Also the empty string can be used to force
# Sentinel to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile "26381.log"
# dir <working-directory>
# Every long running process should have a well-defined working directory.
# For Redis Sentinel to chdir to /tmp at startup is the simplest thing
# for the process to don't interfere with administrative tasks such as
# unmounting filesystems.
dir "/opt/redis-sentinel-3/data"
# Note: master name should not include special characters or spaces.
# The valid charset is A-z 0-9 and the three characters ".-_".
# quorum是一个数字，指明当有多少个sentinel认为一个master失效时(值一般为：sentinel总数/2 + 1)，master才算真正失效
sentinel monitor mymaster 192.168.56.200 6379 2 # mymaster这个名字随便取，客户端访问时会用到

启动sentinel哨兵实例

/usr/local/redis-6.2.14/src/redis-sentinel sentinel.conf

查看sentinel的info信息

/usr/local/redis-6.2.14/src/redis-cli -p 26379 
127.0.0.1:26379> info

sentinel集群启动完毕后，会讲哨兵集群的元素信息写入所有sentinel的配置文件里去（追加在文件的最下面），如下所示：

sentinel known-replica mymaster 192.168.56.200 6381 #代表redis主节点的从节点信息
sentinel known-replica mymaster 192.168.56.200 6380
#代表redis主节点的从节点信息
sentinel known-sentinel mymaster 192.168.56.200 26381 a9e0b5cfa1fc7705e133f8024c3bbbcfbcc73f64 #代表感知到的其他哨兵节点
sentinel known-sentinel mymaster 192.168.56.200 26379 5bc744b420082eb3588741824265d13f1329f51b #代表感知到的其他哨兵

当redis主节点如果挂了，哨兵集群会重新选举出新的redis主节点，同时会修改所有sentinel节点配置文件的集群元数据信息，同时还会修改sentinel文件里之前配置的mymaster对应的端口。

Spring Boot连接哨兵

引入maven依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
</dependency>

Spring Boot 核心配置

application.yml

server:
  prot: 8080

spring:
  redis:
    database: 0
    timeout: 3000
    sentinel:    #哨兵模式
      master: mymaster #主服务器所在集群名称
      nodes: 192.168.56.200:26379,192.168.56.200:26380,192.168.56.200:26381
    lettuce:
      pool:
        max-idle: 50
        min-idle: 10
        max-active: 100
        max-wait: 1000

测试代码

 @RestController
public class JedisSentinelController {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    /**
     * 测试节点挂了哨兵重新选举新的master节点，客户端是否能动态感知到
     * 新的master选举出来后，哨兵会把消息发布出去，客户端实际上是实现了一个消息监听机制，
     * 当哨兵把新master的消息发布出去，客户端会立马感知到新master的信息，从而动态切换访问的masterip
     */
    @GetMapping("/testSentinel")
    public void testSentinel() {
        int i = 1;
        while (true) {
            try {
                stringRedisTemplate.opsForValue().set("warrior:" + i, i + "");
                System.out.println("设置key：warrior:" + i);
                Thread.sleep(2000);
                i++;
            } catch (Exception e) {
                System.out.println("错误：" + e.getMessage());
            }
        }
    }
}