单节点Redis的哨哨兵并发能力是有上限的，要进一步提高Redis的兵集并发能力，就需要搭建主从集群，群原实现读写分离
主节点: 可以对Redis实现读写操作从节点: 只可以对Redis实现读操作但是理讲，当master节点宕机后，解和集群我们就不能写数据到Redis,哨哨兵所以需要搭建一个三节点形成的Sentinel集群，来监管之前的兵集Redis主从集群
Redis提供了哨兵（Sentinel）机制来实现主从集群的自动故障恢复。
哨兵的群原结构如图：
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共包含6个节点，一个主两个从和三个哨兵。理讲这里我们会在同一台虚拟机中开启6个redis实例，解和集群模拟主从集群，哨哨兵信息如下：
IP
PORT
角色
192.168.150.102
6380
master
192.168.150.102
6381
slave
192.168.150.102
6382
slave
192.168.150.102
26379
sentinel
192.168.150.102
26380
sentinel
192.168.150.102
26381
sentinel
哨兵的兵集作用如下：
监控：Sentinel 会不断检查您的master和slave是否按预期工作自动故障恢复：如果master故障Sentinel会将一个slave提升为master。当故障实例恢复后也以新的群原master为主通知：Sentinel充当Redis客户端的服务发现来源，当集群发生故障转移时会将最新信息推送给Redis的理讲客户端要在同一台虚拟机开启6个实例，必须准备6份不同的解和集群配置文件和目录，配置文件所在目录也就是工作目录。 确保下面的源码库配置已经更改（位置也别错）
复制# master mkdir -p /redis-master-slave-sentinel/redis/master/config /redis-master-slave-sentinel/redis/master/data cd /redis-master-slave-sentinel/redis/master/config curl -O -L http://download.redis.io/releases/redis-6.0.20.tar.gz tar -zxvf redis-6.0.20.tar.gz cp /redis-master-slave-sentinel/redis/master/config/redis-6.0.20/redis.conf /redis-master-slave-sentinel/redis/master/config/redis.conf sed -i s/bind 127.0.0.1/bind 0.0.0.0/ /redis-master-slave-sentinel/redis/master/config/redis.conf # slave-1 mkdir -p /redis-master-slave-sentinel/redis/slave-1/config /redis-master-slave-sentinel/redis/slave-1/data cd /redis-master-slave-sentinel/redis/slave-1/config/ cp /redis-master-slave-sentinel/redis/master/config/redis-6.0.20/redis.conf /redis-master-slave-sentinel/redis/slave-1/config/redis.conf sed -i s/bind 127.0.0.1/bind 0.0.0.0/ /redis-master-slave-sentinel/redis/slave-1/config/redis.conf # slave-2 mkdir -p /redis-master-slave-sentinel/redis/slave-2/config /redis-master-slave-sentinel/redis/slave-2/data cd /redis-master-slave-sentinel/redis/slave-2/config/ cp /redis-master-slave-sentinel/redis/master/config/redis-6.0.20/redis.conf /redis-master-slave-sentinel/redis/slave-2/config/redis.conf sed -i s/bind 127.0.0.1/bind 0.0.0.0/ /redis-master-slave-sentinel/redis/slave-2/config/redis.conf #redis-sentinel-1 mkdir -p /redis-master-slave-sentinel/sentinel/redis-sentinel-1 /redis-master-slave-sentinel/sentinel/redis-sentinel-1/s1 cd /redis-master-slave-sentinel/sentinel/redis-sentinel-1 cat >> /redis-master-slave-sentinel/sentinel/redis-sentinel-1/sentinel.conf <<EOF # 配置可参考 http://download.redis.io/redis-stable/sentinel.conf # 配置说明 https://redis.io/topics/sentinel port 26379 dir /tmp sentinel monitor mymaster 192.168.150.102 6380 2 sentinel down-after-milliseconds mymaster 30000 sentinel parallel-syncs mymaster 1 sentinel auth-pass mymaster 123456 sentinel failover-timeout mymaster 180000 sentinel deny-scripts-reconfig yes EOF #redis-sentinel-2 mkdir -p /redis-master-slave-sentinel/sentinel/redis-sentinel-2 /redis-master-slave-sentinel/sentinel/redis-sentinel-2/s2 cd /redis-master-slave-sentinel/sentinel/redis-sentinel-2 cat >> /redis-master-slave-sentinel/sentinel/redis-sentinel-2/sentinel.conf <<EOF # 配置可参考 http://download.redis.io/redis-stable/sentinel.conf # 配置说明 https://redis.io/topics/sentinel port 26379 dir /tmp sentinel monitor mymaster 192.168.150.102 6380 2 sentinel down-after-milliseconds mymaster 30000 sentinel parallel-syncs mymaster 1 sentinel auth-pass mymaster 123456 sentinel failover-timeout mymaster 180000 sentinel deny-scripts-reconfig yes EOF #redis-sentinel-3 mkdir -p /redis-master-slave-sentinel/sentinel/redis-sentinel-3 /redis-master-slave-sentinel/sentinel/redis-sentinel-3/s3 cd /redis-master-slave-sentinel/sentinel/redis-sentinel-3 cat >> /redis-master-slave-sentinel/sentinel/redis-sentinel-3/sentinel.conf <<EOF # 配置可参考 http://download.redis.io/redis-stable/sentinel.conf # 配置说明 https://redis.io/topics/sentinel port 26379 dir /tmp sentinel monitor mymaster 192.168.150.102 6380 2 sentinel down-after-milliseconds mymaster 30000 sentinel parallel-syncs mymaster 1 sentinel auth-pass mymaster 123456 sentinel failover-timeout mymaster 180000 sentinel deny-scripts-reconfig yes EOF1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.61.62.63.64.65.66.67.68.69.70.71.72.73.74.75.76.77.sentinel.conf说明
复制port 26379 dir /tmp sentinel monitor mymaster 192.168.150.102 6380 2 sentinel down-after-milliseconds mymaster 30000 sentinel parallel-syncs mymaster 1 sentinel auth-pass mymaster 123456 sentinel failover-timeout mymaster 180000 sentinel deny-scripts-reconfig yes1.2.3.4.5.6.7.8.sentinel.conf解读
port 26379：是当前sentinel实例的端口sentinel monitor mymaster 192.168.150.102 6380 2：指定主节点信息 ○ mymaster：主节点名称，自定义，任意写 ○ 192.168.150.102 6380：主节点的ip和端口 ○ 2：选举master时的quorum值sentinel auth-pass mymaster 123456 :访问主节点时的密码如果您觉得本文不错，欢迎关注,点赞,收藏支持，您的关注是我坚持的动力！
创建名称为docker-compose-redis-master-slave-sentinel.yml用于安装Redis哨兵集群docker-compose文件
复制version: 3 # 网桥redis -> 方便相互通讯 networks: redis: services: # ============================ ↓↓↓↓↓↓ redis ↓↓↓↓↓↓ ============================ # 主 redis-master: image: redis:6.0.20 # 镜像redis:6.0.20 container_name: redis-master # 容器名为redis-master restart: unless-stopped # 指定容器退出后的重启策略为始终重启，但是不考虑在Docker守护进程启动时就已经停止了的容器 command: redis-server /etc/redis/redis.conf --port 6380 --requirepass 123456 --masterauth 123456 --appendonly no # 启动redis服务并添加密码为：123456, 当主redis下线重启后变成从redis时认证主redis密码：123456, 默认不开启redis-aof方式持久化配置 environment: # 设置环境变量,相当于docker run命令中的-e TZ: Asia/Shanghai LANG: en_US.UTF-8 volumes: # 数据卷挂载路径设置,将本机目录映射到容器目录 - "/redis-master-slave-sentinel/redis/master/data:/data" - "/redis-master-slave-sentinel/redis/master/config/redis.conf:/etc/redis/redis.conf" # `redis.conf`文件内容`http://download.redis.io/redis-stable/redis.conf` ports: # 映射端口 - "6380:6380" # 从1 redis-slave-1: image: redis:6.0.20 # 镜像redis:6.0.20 container_name: redis-slave-1 # 容器名为redis-slave-1 restart: unless-stopped # 指定容器退出后的重启策略为始终重启，但是不考虑在Docker守护进程启动时就已经停止了的容器 command: redis-server /etc/redis/redis.conf --port 6381 --requirepass 123456 --appendonly no --slaveof 192.168.150.102 6380 --masterauth 123456 # 启动redis服务并添加密码为：123456,默认不开启redis-aof方式持久化配置,连接并认证master节点 environment: # 设置环境变量,相当于docker run命令中的-e TZ: Asia/Shanghai LANG: en_US.UTF-8 volumes: # 数据卷挂载路径设置,将本机目录映射到容器目录 - "/redis-master-slave-sentinel/redis/slave-1/data:/data" - "/redis-master-slave-sentinel/redis/slave-1/config/redis.conf:/etc/redis/redis.conf" # `redis.conf`文件内容`http://download.redis.io/redis-stable/redis.conf` ports: # 映射端口 - "6381:6381" depends_on: - redis-master links: - redis-master # 从2 redis-slave-2: image: redis:6.0.20 # 镜像redis:6.0.20 container_name: redis-slave-2 # 容器名为redis-slave-2 restart: unless-stopped # 指定容器退出后的重启策略为始终重启，但是不考虑在Docker守护进程启动时就已经停止了的容器 command: redis-server /etc/redis/redis.conf --port 6382 --requirepass 123456 --appendonly no --slaveof 192.168.150.102 6380 --masterauth 123456 # 启动redis服务并添加密码为：123456,默认不开启redis-aof方式持久化配置,连接并认证master节点 environment: # 设置环境变量,相当于docker run命令中的-e TZ: Asia/Shanghai LANG: en_US.UTF-8 volumes: # 数据卷挂载路径设置,将本机目录映射到容器目录 - "/redis-master-slave-sentinel/redis/slave-2/data:/data" - "/redis-master-slave-sentinel/redis/slave-2/config/redis.conf:/etc/redis/redis.conf" # `redis.conf`文件内容`http://download.redis.io/redis-stable/redis.conf` ports: # 映射端口 - "6382:6382" depends_on: - redis-master links: - redis-master # ============================ ↓↓↓↓↓↓ sentinel ↓↓↓↓↓↓ ============================ redis-sentinel-1: image: redis:6.0.20 # 镜像redis:6.0.20 container_name: redis-sentinel-1 # 容器名为redis-sentinel-1 restart: unless-stopped # 指定容器退出后的重启策略为始终重启，但是不考虑在Docker守护进程启动时就已经停止了的香港云服务器容器 command: redis-sentinel /etc/redis/sentinel.conf environment: # 设置环境变量,相当于docker run命令中的-e TZ: Asia/Shanghai LANG: en_US.UTF-8 ports: - "26379:26379" volumes: - "/redis-master-slave-sentinel/sentinel/redis-sentinel-1/sentinel.conf:/etc/redis/sentinel.conf" # `sentinel.conf`文件内容`http://download.redis.io/redis-stable/sentinel.conf` depends_on: - redis-master - redis-slave-1 - redis-slave-2 links: - redis-master - redis-slave-1 - redis-slave-2 redis-sentinel-2: image: redis:6.0.20 # 镜像redis:6.0.20 container_name: redis-sentinel-2 # 容器名为redis-sentinel-2 restart: unless-stopped # 指定容器退出后的重启策略为始终重启，但是不考虑在Docker守护进程启动时就已经停止了的容器 command: redis-sentinel /etc/redis/sentinel.conf environment: # 设置环境变量,相当于docker run命令中的-e TZ: Asia/Shanghai LANG: en_US.UTF-8 ports: - "26380:26379" volumes: - "/redis-master-slave-sentinel/sentinel/redis-sentinel-2/sentinel.conf:/etc/redis/sentinel.conf" # `sentinel.conf`文件内容`http://download.redis.io/redis-stable/sentinel.conf` depends_on: - redis-master - redis-slave-1 - redis-slave-2 - redis-sentinel-1 links: - redis-master - redis-slave-1 - redis-slave-2 redis-sentinel-3: image: redis:6.0.20 # 镜像redis:6.0.20 container_name: redis-sentinel-3 # 容器名为redis-sentinel-3 restart: unless-stopped # 指定容器退出后的重启策略为始终重启，但是不考虑在Docker守护进程启动时就已经停止了的容器 command: redis-sentinel /etc/redis/sentinel.conf environment: # 设置环境变量,相当于docker run命令中的-e TZ: Asia/Shanghai LANG: en_US.UTF-8 ports: - "26381:26379" volumes: - "/redis-master-slave-sentinel/sentinel/redis-sentinel-3/sentinel.conf:/etc/redis/sentinel.conf" # `sentinel.conf`文件内容`http://download.redis.io/redis-stable/sentinel.conf` depends_on: - redis-master - redis-slave-1 - redis-slave-2 - redis-sentinel-1 - redis-sentinel-2 links: - redis-master - redis-slave-1 - redis-slave-21.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.61.62.63.64.65.66.67.68.69.70.71.72.73.74.75.76.77.78.79.80.81.82.83.84.85.86.87.88.89.90.91.92.93.94.95.96.97.98.99.100.101.102.103.104.105.106.107.108.109.110.111.112.113.114.115.116.117.118.119.120.121.122.123.124.125.运行 -- 哨兵模式（sentinel监视redis主从服务，当某个master服务下线时，自动将该master下的某个从服务升级为master服务替代已下线的master服务继续处理请求 -- 即主节点切换）
复制docker-compose -f docker-compose-redis-master-slave-sentinel.yml -p redis up -d1.
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发现主节点从master节点，转换为slave-2节点
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发现现在从节点只剩一个
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发现master节点添加回来了，但是变成了从节点
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哨兵master自己从当前集群中的slave节点中选出一个新的master，原则是
1-首先会判断slave节点与master节点断开时间长短，如果超过指定值（down-after-milliseconds * 10）则会排除该slave节点2-然后判断slave节点的slave-priority值，越小优先级越高，如果是0则永不参与选举3-如果slave-prority一样，则判断slave节点的offset值，越大说明数据越新，优先级越高4-最后是判断slave节点的站群服务器运行id大小，越小优先级越高。Sentinel基于心跳机制监测服务状态，每隔1秒向集群的每个实例发送ping命令：
主观下线：如果某sentinel节点发现某实例未在规定时间响应，则认为该实例主观下线。客观下线：若超过指定数量（quorum）的sentinel都认为该实例主观下线，则该实例客观下线。quorum值最好超过Sentinel实例数量的一半。
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Sentinel的三个作用是什么
监控故障转移通知Sentinel如何判断一个redis实例是否健康
每隔1秒发送一次ping命令，如果超过一定时间没有相向则认为是主观下线如果大多数sentinel都认为实例主观下线，则判定服务下线(责任编辑：系统运维)