Redis 8. redis的复制(Master/Slave)

电玩女神 2022-03-29 21:06 182阅读 0赞

# Redis #

*@Author:hanguixian*  
*@Email:hn\_hanguixian@163.com*

## 八 Redis的复制(Master/Slave) ##

### 1 是什么 ###

*  官网
    
     *  英文：[https://redis.io/topics/replication][https_redis.io_topics_replication]
     *  中文：[http://www.redis.cn/topics/replication.html][http_www.redis.cn_topics_replication.html]
 *  就是我们所说的主从复制，主机数据更新后根据配置和策略，自动同步到备机的master/slaver机制，Master以写为主，Slave以读为主

### 2 能干嘛 ###

*  读写分离
 *  容灾恢复

### 3 使用 ###

*  配从(库)不配主(库)
 *  从库配置：slaveof 主库IP 主库端口
    
     *  每次与master断开之后，都需要重新连接，除非你配置进redis.conf文件
     *  info replication
 *  修改配置文件细节操作
    
     *  拷贝多个redis.conf文件
     *  开启daemonize yes
     *  pid文件名字
     *  指定端口
     *  log文件名字
     *  dump.rdb名字

pidfile /var/run/redis_6380.pid
    port 6380
    logfile "6380.log"
    dbfilename dump6380.rdb
    appendfilename "appendonly6380.aof"

*  三种方式
    
     *  一主二仆
        
         *  一个Master两个Slave
         *  日志查看
            
             *  主机日志
             *  备机日志
             *  info replication
     *  薪火相传
        
         *  上一个Slave可以是下一个slave的Master，Slave同样可以接收其他slaves的连接和同步请求，那么该slave作为了链条中下一个的master,可以有效减轻master的写压力
         *  中途变更转向:会清除之前的数据，重新建立拷贝最新的
         *  slaveof 新主库IP 新主库端口
     *  反客为主
        
         *  SLAVEOF no one
            
             *  使当前数据库停止与其他数据库的同步，转成主数据库

### 4 示例 ###

#### 4.1 一主二仆 ####

##端口:6379##
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_6379.conf 
    [root@xxxmmm bin]# redis-cli -p 6379
    127.0.0.1:6379> info replication
    # Replication
    ##############启动起来是master################################
    role:master
    connected_slaves:0
    master_replid:d33a8a6e37b2f0ca28ab7557c12acc8bf1d58751
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:0
    second_repl_offset:-1
    repl_backlog_active:0
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:0
    repl_backlog_histlen:0
    127.0.0.1:6379> KEYS *
    (empty list or set)
    127.0.0.1:6379> set k1 v1
    OK
    127.0.0.1:6379> set k2 v2
    OK
    127.0.0.1:6379> info replication
    # Replication
    role:master
    ###################配置了两个从库#######################################
    connected_slaves:2
    slave0:ip=127.0.0.1,port=6380,state=online,offset=70,lag=0
    slave1:ip=127.0.0.1,port=6381,state=online,offset=70,lag=1
    master_replid:458473b6141ebd0012dd6698913afe6be6b75c7d
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:70
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:70
    127.0.0.1:6379> set k3 v3
    OK
    127.0.0.1:6379> SHUTDOWN
    not connected> exit
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_6379.conf 
    [root@xxxmmm bin]# redis-cli -p 6379
    127.0.0.1:6379> keys *
    1) "k1"
    2) "k3"
    3) "k2"
    127.0.0.1:6379> set k4 v4
    OK
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:1
    slave0:ip=127.0.0.1,port=6381,state=online,offset=192,lag=1
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:192
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:192
    
    ###############################################################################
    ###端口：6380###
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_6380.conf 
    [root@xxxmmm bin]# redis-cli -p 6380
    127.0.0.1:6380> info replication
    # Replication
    role:master
    ###############启动起来都是master###############################
    connected_slaves:0
    master_replid:b25d2d448e71cce4aba5168560f874715be8e67c
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:0
    second_repl_offset:-1
    repl_backlog_active:0
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:0
    repl_backlog_histlen:0
    127.0.0.1:6380> keys *
    (empty list or set)
    ####################从库配置######################################
    127.0.0.1:6380> SLAVEOF 127.0.0.1 6379
    OK
    127.0.0.1:6380> info replication
    # Replication
    ####################从库配置后变成了slave##########################
    role:slave
    master_host:127.0.0.1
    master_port:6379
    #########################连接状态up#################################
    master_link_status:up
    master_last_io_seconds_ago:2
    master_sync_in_progress:0
    slave_repl_offset:14
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:458473b6141ebd0012dd6698913afe6be6b75c7d
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:14
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:14
    127.0.0.1:6380> keys *
    1) "k1"
    2) "k2"
    127.0.0.1:6380> keys *
    1) "k3"
    2) "k1"
    3) "k2"
    #####################从库默认不可写#####################################
    127.0.0.1:6380> set k666 v666
    (error) READONLY You can't write against a read only replica.
    127.0.0.1:6380> info replication
    # Replication
    ###################主库挂了后，salve没有变成master#######################
    role:slave
    master_host:127.0.0.1
    master_port:6379
    #######################主库挂了后，连接断开################################
    master_link_status:down
    master_last_io_seconds_ago:-1
    master_sync_in_progress:0
    slave_repl_offset:276
    master_link_down_since_seconds:9
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:458473b6141ebd0012dd6698913afe6be6b75c7d
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:276
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:276
    127.0.0.1:6380> keys *
    1) "k3"
    2) "k1"
    3) "k2"
    127.0.0.1:6380> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    ##################主库重新启动后，连接状态up########################################
    master_link_status:up
    master_last_io_seconds_ago:7
    master_sync_in_progress:0
    slave_repl_offset:14
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:14
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:14
    127.0.0.1:6380> keys *
    1) "k3"
    2) "k4"
    3) "k1"
    4) "k2"
    127.0.0.1:6380> SHUTDOWN
    not connected> exit
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_6380.conf 
    [root@xxxmmm bin]# redis-cli -p 6380
    127.0.0.1:6380> keys *
    1) "k4"
    2) "k2"
    3) "k1"
    4) "k3"
    127.0.0.1:6380> info replication
    # Replication
    ##################从库断开重连后，变成了master########################
    role:master
    connected_slaves:0
    master_replid:97e8893dcd75b4a4a0af650dd09a13a37b8f6923
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:0
    second_repl_offset:-1
    repl_backlog_active:0
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:0
    repl_backlog_histlen:0
    ########################需要重新配置##################################
    127.0.0.1:6380> SLAVEOF 127.0.0.1 6379
    OK
    127.0.0.1:6380> keys *
    1) "k2"
    2) "k1"
    3) "k4"
    4) "k3"
    
    
    ##########################################################################
    ###端口：6381###
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_6381.conf 
    [root@xxxmmm bin]# redis-cli -p 6381
    127.0.0.1:6381> KEYS *
    (empty list or set)
    127.0.0.1:6381> info repalication
    127.0.0.1:6381> info replication
    # Replication
    role:master
    connected_slaves:0
    master_replid:d1d3fc86699f0947975c1d7986c95e0d3a846602
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:0
    second_repl_offset:-1
    repl_backlog_active:0
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:0
    repl_backlog_histlen:0
    127.0.0.1:6381> SLAVEOF 127.0.0.1 6379
    OK
    127.0.0.1:6381> keys *
    1) "k1"
    2) "k2"
    127.0.0.1:6381> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    master_link_status:down
    master_last_io_seconds_ago:-1
    master_sync_in_progress:0
    slave_repl_offset:276
    master_link_down_since_seconds:20
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:458473b6141ebd0012dd6698913afe6be6b75c7d
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:276
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:57
    repl_backlog_histlen:220
    127.0.0.1:6381> keys *
    1) "k1"
    2) "k4"
    3) "k2"
    
    ##########################################################################
    ###端口查看###
    [root@xxxmmm bin]# ps -ef|grep redis
    root     17162     1  0 21:59 ?        00:00:00 redis-server 127.0.0.1:6379
    root     17171 17116  0 22:00 pts/0    00:00:00 redis-cli -p 6379
    root     17248     1  0 22:07 ?        00:00:00 redis-server 127.0.0.1:6380
    root     17252 17174  0 22:07 pts/1    00:00:00 redis-cli -p 6380
    root     17254     1  0 22:07 ?        00:00:00 redis-server 127.0.0.1:6381
    root     17258 17222  0 22:08 pts/2    00:00:00 redis-cli -p 6381
    root     17290 17261  0 22:10 pts/3    00:00:00 grep --color=auto redis

#### 4.2 薪火相传 ####

###################端口：6379##########################
    [root@xxxmmm bin]# redis-cli -p 6379
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:2
    slave0:ip=127.0.0.1,port=6381,state=online,offset=119626,lag=0
    slave1:ip=127.0.0.1,port=6380,state=online,offset=119626,lag=1
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:119626
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:119626
    127.0.0.1:6379> set kuu vuu
    OK
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:1
    slave0:ip=127.0.0.1,port=6380,state=online,offset=120030,lag=1
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:120030
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:120030
    
    ###################端口：6380##########################
    [root@xxxmmm bin]# redis-cli -p 6380
    127.0.0.1:6380> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    master_link_status:up
    master_last_io_seconds_ago:1
    master_sync_in_progress:0
    slave_repl_offset:119710
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:119710
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:221
    repl_backlog_histlen:119490
    127.0.0.1:6380> keys *
    1) "k2"
    2) "k1"
    3) "k4"
    4) "k3"
    127.0.0.1:6380> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    master_link_status:up
    master_last_io_seconds_ago:6
    master_sync_in_progress:0
    slave_repl_offset:119850
    slave_priority:100
    slave_read_only:1
    connected_slaves:1
    slave0:ip=127.0.0.1,port=6381,state=online,offset=119850,lag=1
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:119850
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:221
    repl_backlog_histlen:119630
    127.0.0.1:6380> keys *
    1) "k2"
    2) "k1"
    3) "k4"
    4) "k3"
    127.0.0.1:6380> set km vm11
    (error) READONLY You can't write against a read only replica.
    127.0.0.1:6380> keys *
    1) "k4"
    2) "k1"
    3) "k2"
    4) "kuu"
    5) "k3"
    
    ###################端口：6381##########################
    [root@xxxmmm bin]# redis-cli -p 6381
    127.0.0.1:6381> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    master_link_status:up
    master_last_io_seconds_ago:3
    master_sync_in_progress:0
    slave_repl_offset:119780
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:119780
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:119780
    127.0.0.1:6381> keys *
    1) "k1"
    2) "k4"
    3) "k2"
    4) "k3"
    127.0.0.1:6381> SLAVEOF 127.0.0.1 6380
    OK
    127.0.0.1:6381> keys *
    1) "k1"
    2) "k4"
    3) "k2"
    4) "k3"
    127.0.0.1:6381> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6380
    master_link_status:up
    master_last_io_seconds_ago:8
    master_sync_in_progress:0
    slave_repl_offset:119836
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:119836
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:119836
    127.0.0.1:6381> keys *
    1) "k3"
    2) "k2"
    3) "k4"
    4) "k1"
    5) "kuu"

#### 4.3 反客为主 ####

#################端口：6379########################################
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:1
    slave0:ip=127.0.0.1,port=6380,state=online,offset=120030,lag=1
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:120030
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:120030
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:0
    master_replid:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:120744
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:120744
    
    #################端口：6380########################################
    127.0.0.1:6380> SLAVEOF no one
    OK
    127.0.0.1:6380> info replication
    # Replication
    role:master
    connected_slaves:1
    slave0:ip=127.0.0.1,port=6381,state=online,offset=120786,lag=1
    master_replid:d411a5594443b42429ae25d38c3269e28c743d27
    master_replid2:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_repl_offset:120786
    second_repl_offset:120745
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:221
    repl_backlog_histlen:120566
    127.0.0.1:6380> keys *
    1) "k4"
    2) "k1"
    3) "k2"
    4) "kuu"
    5) "k3"
    ###############端口：6381########################################
    127.0.0.1:6381> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6380
    master_link_status:up
    master_last_io_seconds_ago:2
    master_sync_in_progress:0
    slave_repl_offset:120842
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:d411a5594443b42429ae25d38c3269e28c743d27
    master_replid2:568ced83b66508a1bd5ab472ea60a81242f3141e
    master_repl_offset:120842
    second_repl_offset:120745
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:120842

### 5 复制原理 ###

*  slave启动成功连接到master后会发送一个sync命令
 *  Master接到命令启动后台的存盘进程，同时收集所有接收到的用于修改数据集命令，在后台进程执行完毕之后，master将传送整个数据文件到slave,以完成一次完全同步
 *  全量复制：而slave服务在接收到数据库文件数据后，将其存盘并加载到内存中。
 *  增量复制：Master继续将新的所有收集到的修改命令依次传给slave,完成同步
 *  但是只要是重新连接master,一次完全同步（全量复制)将被自动执行

### 6 哨兵模式(sentinel) ###

#### 6.1 是什么 ####

*  反客为主的自动版，能够后台监控主机是否故障，如果故障了根据投票数自动将从库转换为主库

#### 6.2 使用 ####

*  1 调整结构，6379带着80、81
 *  2 自定义的/myredis目录下新建sentinel.conf文件，名字绝不能错
 *  3 配置哨兵,填写内容
    
     *  sentinel monitor 被监控数据库名字(自己起名字) 127.0.0.1 6379 1
     *  上面最后一个数字1，表示主机挂掉后salve投票看让谁接替成为主机，得票数多少后成为主机
 *  4 启动哨兵
    
     *  redis-sentinel /myredis/sentinel.conf

####端口：6379###
    [root@xxxmmm bin]# redis-cli -p 6379
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:2
    slave0:ip=127.0.0.1,port=6381,state=online,offset=120814,lag=0
    slave1:ip=127.0.0.1,port=6380,state=online,offset=120814,lag=1
    master_replid:75a7031ef8688d571732a359971c32ccbe8cccbe
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:120814
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:120745
    repl_backlog_histlen:70
    127.0.0.1:6379> SHUTDOWN
    not connected> exit
    [root@xxxmmm bin]# ps -ef|grep redis
    root     17254     1  0 Dec10 ?        00:02:18 redis-server 127.0.0.1:6381
    root     17338     1  0 Dec10 ?        00:02:16 redis-server 127.0.0.1:6380
    root     20022 20004  0 22:39 pts/1    00:00:00 redis-cli -p 6380
    root     20042 20025  0 22:39 pts/2    00:00:00 redis-cli -p 6381
    root     20075 20054  0 22:44 pts/3    00:00:00 redis-sentinel *:26379 [sentinel]
    root     20082 19980  0 22:46 pts/0    00:00:00 grep --color=auto redis
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_63
    redis_6379.conf  redis_6380.conf  redis_6381.conf  
    [root@xxxmmm bin]# redis-server /hanguixian/myredis/redis_6379.conf 
    [root@xxxmmm bin]# redis-cli -p 6379
    127.0.0.1:6379> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6381
    master_link_status:up
    master_last_io_seconds_ago:1
    master_sync_in_progress:0
    slave_repl_offset:191974
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:989c58ab7281d1858cb244f0e12ea18f50c8e3cd
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:191974
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:189945
    repl_backlog_histlen:2030
    
    ###############端口:6380#####################
    127.0.0.1:6380> SLAVEOF 127.0.0.1 6379
    OK
    127.0.0.1:6380> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    master_link_status:up
    master_last_io_seconds_ago:1
    master_sync_in_progress:0
    slave_repl_offset:120800
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:75a7031ef8688d571732a359971c32ccbe8cccbe
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:120800
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:120801
    repl_backlog_histlen:0
    127.0.0.1:6380> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6381
    master_link_status:up
    master_last_io_seconds_ago:0
    master_sync_in_progress:0
    slave_repl_offset:126927
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:989c58ab7281d1858cb244f0e12ea18f50c8e3cd
    master_replid2:75a7031ef8688d571732a359971c32ccbe8cccbe
    master_repl_offset:126927
    second_repl_offset:123836
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:120801
    repl_backlog_histlen:6127
    
    ######################端口：6381######################################
    127.0.0.1:6381> SLAVEOF 127.0.0.1 6379
    OK
    127.0.0.1:6381> info replication
    # Replication
    role:slave
    master_host:127.0.0.1
    master_port:6379
    master_link_status:up
    master_last_io_seconds_ago:0
    master_sync_in_progress:0
    slave_repl_offset:120758
    slave_priority:100
    slave_read_only:1
    connected_slaves:0
    master_replid:75a7031ef8688d571732a359971c32ccbe8cccbe
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:120758
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:120745
    repl_backlog_histlen:14
    127.0.0.1:6381> KEYS *
    1) "k2"
    2) "k3"
    3) "k4"
    4) "k1"
    5) "kuu"
    127.0.0.1:6381> info replication
    # Replication
    role:master
    connected_slaves:1
    slave0:ip=127.0.0.1,port=6380,state=online,offset=127320,lag=1
    master_replid:989c58ab7281d1858cb244f0e12ea18f50c8e3cd
    master_replid2:75a7031ef8688d571732a359971c32ccbe8cccbe
    master_repl_offset:127320
    second_repl_offset:123836
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:120745
    repl_backlog_histlen:6576

###############编写：sentinel.conf####################################
    sentinel monitor my6379 127.0.0.1 6379 1
    ##################运行###############################################
    [root@xxxmmm bin]# redis-sentinel /hanguixian/myredis/sentinel.conf 
    20075:X 12 Dec 2018 22:44:52.701 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
    20075:X 12 Dec 2018 22:44:52.701 # Redis version=5.0.0, bits=64, commit=00000000, modified=0, pid=20075, just started
    20075:X 12 Dec 2018 22:44:52.701 # Configuration loaded
                    _._                                                  
               _.-``__ ''-._ _.-`` `.  `_. ''-._ Redis 5.0.0 (00000000/0) 64 bit .-`` .-```. ```\/ _.,_ ''-._ ( ' , .-`  | `, ) Running in sentinel mode |`-._`-...-` __...-.``-._|'` _.-'| Port: 26379 | `-._ `._ / _.-'    |     PID: 20075
      `-._ `-._  `-./ _.-' _.-' |`-._`-._ `-.__.-'    _.-'_.-'|                                  
     |    `-._`-._        _.-'_.-'    |           http://redis.io        
      `-._ `-._`-.__.-'_.-' _.-' |`-._`-._ `-.__.-' _.-'_.-'|                                  
     |    `-._`-._        _.-'_.-'    |                                  
      `-._ `-._`-.__.-'_.-' _.-' `-._    `-.__.-' _.-' `-._        _.-' `-.__.-'                                               
    
    20075:X 12 Dec 2018 22:44:52.703 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
    20075:X 12 Dec 2018 22:44:52.728 # Sentinel ID is 26709d9a12e01632f557b0310533f3fc8806e57c
    20075:X 12 Dec 2018 22:44:52.728 # +monitor master my6379 127.0.0.1 6379 quorum 1
    20075:X 12 Dec 2018 22:44:52.729 * +slave slave 127.0.0.1:6381 127.0.0.1 6381 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:44:52.748 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.764 # +sdown master my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.764 # +odown master my6379 127.0.0.1 6379 #quorum 1/1
    20075:X 12 Dec 2018 22:46:04.764 # +new-epoch 1
    20075:X 12 Dec 2018 22:46:04.764 # +try-failover master my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.793 # +vote-for-leader 26709d9a12e01632f557b0310533f3fc8806e57c 1
    20075:X 12 Dec 2018 22:46:04.793 # +elected-leader master my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.793 # +failover-state-select-slave master my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.855 # +selected-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.855 * +failover-state-send-slaveof-noone slave 127.0.0.1:6381 127.0.0.1 6381 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:04.917 * +failover-state-wait-promotion slave 127.0.0.1:6381 127.0.0.1 6381 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:05.915 # +promoted-slave slave 127.0.0.1:6381 127.0.0.1 6381 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:05.915 # +failover-state-reconf-slaves master my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:05.970 * +slave-reconf-sent slave 127.0.0.1:6380 127.0.0.1 6380 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:06.909 * +slave-reconf-inprog slave 127.0.0.1:6380 127.0.0.1 6380 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:06.909 * +slave-reconf-done slave 127.0.0.1:6380 127.0.0.1 6380 @ my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:06.974 # +failover-end master my6379 127.0.0.1 6379
    20075:X 12 Dec 2018 22:46:06.974 # +switch-master my6379 127.0.0.1 6379 127.0.0.1 6381
    20075:X 12 Dec 2018 22:46:06.974 * +slave slave 127.0.0.1:6380 127.0.0.1 6380 @ my6379 127.0.0.1 6381
    20075:X 12 Dec 2018 22:46:06.974 * +slave slave 127.0.0.1:6379 127.0.0.1 6379 @ my6379 127.0.0.1 6381
    20075:X 12 Dec 2018 22:46:36.998 # +sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ my6379 127.0.0.1 6381
    20075:X 12 Dec 2018 23:02:41.759 # -sdown slave 127.0.0.1:6379 127.0.0.1 6379 @ my6379 127.0.0.1 6381
    20075:X 12 Dec 2018 23:02:51.689 * +convert-to-slave slave 127.0.0.1:6379 127.0.0.1 6379 @ my6379 127.0.0.1 6381
    
    ###########################再次查看sentinel.conf##########################################
    sentinel myid 26709d9a12e01632f557b0310533f3fc8806e57c
    # Generated by CONFIG REWRITE
    port 26379
    dir "/usr/local/bin"
    sentinel deny-scripts-reconfig yes
    sentinel monitor my6379 127.0.0.1 6381 1
    sentinel config-epoch my6379 1
    sentinel leader-epoch my6379 1
    sentinel known-replica my6379 127.0.0.1 6379
    sentinel known-replica my6379 127.0.0.1 6380
    sentinel current-epoch 1

[https_redis.io_topics_replication]: https://redis.io/topics/replication
[http_www.redis.cn_topics_replication.html]: http://www.redis.cn/topics/replication.html