Redis哨兵模式（Sentinel）的搭建与配置

Redis 哨兵模式（Sentinel）是一个自动监控处理 redis 间故障节点转移工作的一个redis服务端实例，它不提供数据存储服务，只进行普通 redis 节点监控管理，使用redis哨兵模式可以实现redis服务端故障的自动化转移。

一、搭建redis主从集群

1、创建3个redis实例

关于redis的搭建，可以参考历史文章。

https://mp.weixin.qq.com/s/RaWy0sqRxcAti1qbv-GbZQ

如果有编译好的二进制文件，则直接部署redis实例即可。

创建三个redis实例所需的目录，生产环境需独立部署在不同主机上，提高稳定性。

mkdir-p/data/redis
cd/data/redis/
mkdirredis6379redis6380redis6381
cdredis6379
vimredis.conf
#添加如下配置
bind0.0.0.0
protected-modeno
port6379
tcp-backlog511
timeout30
tcp-keepalive300
daemonizeyes
supervisedno
pidfile/data/redis/redis6379/redis_6379.pid
loglevelnotice
logfile"/data/redis/redis6379/redis6379.log"
databases16
stop-writes-on-bgsave-erroryes
rdbcompressionyes
rdbchecksumyes
dbfilenamedump.rdb
dir/data/redis/redis6379
masterauth123456
slave-serve-stale-datayes
slave-read-onlyyes
#将配置文件拷贝到其他2个实例的目录下
cpredis.conf  ../redis6380.conf
cpredis.conf ../redis6381.conf
sed-i"s#6379#6380#g"  ../redis6380/redis.conf
sed-i"s#6379#6381#g"  ../redis6381/redis.conf
#redis实例不建议使用root账号启动，单独创建一个redis用户，并修改redis相关目录的权限
useraddredis
chown-Rredis:redis/data/redis
su-redis
#启动三个redis实例
redis-server/data/redis/redis6379/redis.conf
redis-server/data/redis/redis6380/redis.conf
redis-server/data/redis/redis6381/redis.conf

2、配置主从同步

进入2个实例，配置同步，配置完成后去主节点检查一下是否正常。

[redis@testredis6379]$redis-cli-p6380-a"123456"
Warning: Usingapasswordwith'-a'optiononthecommandlineinterfacemaynotbesafe.
127.0.0.1:6380>slaveof127.0.0.16379
OK
127.0.0.1:6380>exit
[redis@testredis6379]$redis-cli-p6381-a"123456"
Warning: Usingapasswordwith'-a'optiononthecommandlineinterfacemaynotbesafe.
127.0.0.1:6381>slaveof127.0.0.16379
OK
127.0.0.1:6381>exit
[redis@testredis6379]$redis-cli-p6379-a"123456"
Warning: Usingapasswordwith'-a'optiononthecommandlineinterfacemaynotbesafe.
127.0.0.1:6379>inforeplication
#Replication
role:master
connected_slaves:2
slave0:ip=127.0.0.1,port=6380,state=online,offset=42,lag=0
slave1:ip=127.0.0.1,port=6381,state=online,offset=42,lag=1
master_replid:b8a19f5afae13d3da38b359244dc0f560df03176
master_replid2:0000000000000000000000000000000000000000
master_repl_offset:42
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:42
127.0.0.1:6379>

可见当前主从同步已建立。

二、哨兵模式搭建

1、创建3个哨兵实例

mkdir-p/data/redis/redis_sentinel/
cd/data/redis/redis_sentinel/
mkdirsentinel26379sentinel26380sentinel26381
cdsentinel26379
#初始化配置文件如下
vimredis_sentinel_26379.conf
bind0.0.0.0
port26379
daemonizeyes
dir"/data/redis/redis_sentinel/sentinel26379"
pidfile"/data/redis/redis_sentinel/sentinel26379/redis_sentinel26379.pid"
logfile"/data/redis/redis_sentinel/sentinel26379/redis_sentinel26379.log"
#GeneratedbyCONFIGREWRITE
sentineldeny-scripts-reconfigyes
sentinelmonitortestdb127.0.0.163792
sentineldown-after-millisecondstestdb5000
sentinelauth-passtestdb123456
#配置文件拷贝至另2个实例
cpredis_sentinel_26379.conf   ../sentinel26380/redis_sentinel_26380.conf
sed-i"s#26379#26380#g"  ../sentinel26380/redis_sentinel_26380.conf
cpredis_sentinel_26379.conf   ../sentinel26381/redis_sentinel_26381.conf
sed-i"s#26379#26381#g"  ../sentinel26381/redis_sentinel_26381.conf

配置文件主要参数说明：

参数名	说明
bind	绑定的可以访问的主机IP，0.0.0.0 代表不限制
port	哨兵实例的端口
sentinel monitor testdb 127.0.0.1 6379 1	testdb任意定义，哨兵集群名称，127.0.0.1 6379 redis实例主节点；1 代表当1个哨兵实例判断主库不可用则进行转移，生产环境节点数要配置多一点
sentinel down-after-milliseconds testdb 5000	testdb同上，down-after-milliseconds代表 master 最长响应时间，超过这个时间就主观判断它下线，5000 代表5000ms,即5s
sentinel auth-pass testdb 123456	123456 是redis实例的登录密码

2、启动哨兵实例

redis-sentinel  /data/redis/redis_sentinel/sentinel26379/redis_sentinel_26379.conf 
redis-sentinel  /data/redis/redis_sentinel/sentinel26380/redis_sentinel_26380.conf 
redis-sentinel  /data/redis/redis_sentinel/sentinel26381/redis_sentinel_26381.conf

启动后配置文件会自动新增如下红框中的内容。

登录哨兵实例查看。

redis-cli-p26379

3、测试

测试将主节点down机。

redis-cli-p6379-a123456shutdown

再查看哨兵找那个的master结果，如下：

日志信息如下：

1895:X29Apr23:57:31.778#+sdownmastertestdb127.0.0.16379
1895:X29Apr23:57:31.779#+odownmastertestdb127.0.0.16379#quorum1/1
1895:X29Apr23:57:31.779#+new-epoch1
1895:X29Apr23:57:31.779#+try-failovermastertestdb127.0.0.16379
1895:X29Apr23:57:31.795#+vote-for-leader4928b4d4dfd762cd50fa540b7a0903d2be3b0f951
1895:X29Apr23:57:31.796#+elected-leadermastertestdb127.0.0.16379
1895:X29Apr23:57:31.796#+failover-state-select-slavemastertestdb127.0.0.16379
1895:X29Apr23:57:31.862#+selected-slaveslave127.0.0.1:6380127.0.0.16380@testdb127.0.0.16379
1895:X29Apr23:57:31.862*+failover-state-send-slaveof-nooneslave127.0.0.1:6380127.0.0.16380@testdb127.0.0.16379
1895:X29Apr23:57:31.991*+failover-state-wait-promotionslave127.0.0.1:6380127.0.0.16380@testdb127.0.0.16379
1895:X29Apr23:57:32.223#+promoted-slaveslave127.0.0.1:6380127.0.0.16380@testdb127.0.0.16379
1895:X29Apr23:57:32.223#+failover-state-reconf-slavesmastertestdb127.0.0.16379
1895:X29Apr23:57:32.273*+slave-reconf-sentslave127.0.0.1:6381127.0.0.16381@testdb127.0.0.16379
1895:X29Apr23:57:33.231*+slave-reconf-inprogslave127.0.0.1:6381127.0.0.16381@testdb127.0.0.16379
1895:X29Apr23:57:33.231*+slave-reconf-doneslave127.0.0.1:6381127.0.0.16381@testdb127.0.0.16379
1895:X29Apr23:57:33.296#+failover-endmastertestdb127.0.0.16379
1895:X29Apr23:57:33.296#+switch-mastertestdb127.0.0.16379127.0.0.16380
1895:X29Apr23:57:33.297*+slaveslave127.0.0.1:6381127.0.0.16381@testdb127.0.0.16380
1895:X29Apr23:57:33.297*+slaveslave127.0.0.1:6379127.0.0.16379@testdb127.0.0.16380
1895:X29Apr23:57:38.356#+sdownslave127.0.0.1:6379127.0.0.16379@testdb127.0.0.16380