使用主要命令

config set slave-priority <parameter>
config get slave-priority <parameter>
Config rewrite
sentinel failover <parameter>

目标：把主库切换到192.168.2.101上

1.获取三个节点的优先级，值越小优先级越高
    192.168.2.100:8000> config get slave-priority
    1) "slave-priority"
    2) "10"
 
    192.168.2.101:8000> config get slave-priority
    1) "slave-priority"
    2) "50"
 
    192.168.2.102:8000> config get slave-priority
    1) "slave-priority"
    2) "200"
 
 
2.将 192.168.2.101 优先级调整至 5，或将192.168.2.100的有限制调制 100
    192.168.2.100:8000> config set slave-priority 100
    192.168.2.100:8000> config get slave-priority
    1) "slave-priority"
    2) "100"
    192.168.2.100:8000> config rewrite    --执行该命令前，需手动将配置文件备份   
 
     
3.退出再次确认三节点优先级
    192.168.2.100:8000> config get slave-priority
    1) "slave-priority"
    2) "100"
     
    192.168.2.101:8000> config get slave-priority
    1) "slave-priority"
    2) "50"
     
    192.168.2.102:8000> config get slave-priority
    1) "slave-priority"
    2) "200"
     
    192.168.2.101的 slave-priority 最小，也就是优先级最高
     
4.登录Sentinel，确定name
    [root@db1 src]# ./redis-cli -p 28000
    127.0.0.1:28000> info sentinel
    # Sentinel
    sentinel_masters:1
    sentinel_tilt:0
    sentinel_running_scripts:0
    sentinel_scripts_queue_length:0
    sentinel_simulate_failure_flags:0
    master0:name=mymaster,status=ok,address=192.168.2.100:8000,slaves=2,sentinels=3
    127.0.0.1:28000>
 
    进行切换 
    127.0.0.1:28000>  sentinel failover mymaster
    OK
    127.0.0.1:28000>
     
     
    日志：
    2157:X 15 May 20:30:18.980 # +new-epoch 7
    2157:X 15 May 20:30:20.048 # +config-update-from sentinel f9ef2f710b001f20716427fc39bf8284a86bfd3e 192.168.2.100 28000 @ mymaster 192.168.2.100 8000
    2157:X 15 May 20:30:20.048 # +switch-master mymaster 192.168.2.100 8000 192.168.2.101 8000
    2157:X 15 May 20:30:20.049 * +slave slave 192.168.2.102:8000 192.168.2.102 8000 @ mymaster 192.168.2.101 8000
    2157:X 15 May 20:30:20.049 * +slave slave 192.168.2.100:8000 192.168.2.100 8000 @ mymaster 192.168.2.101 8000
    2157:X 15 May 20:30:30.129 * +convert-to-slave slave 192.168.2.100:8000 192.168.2.100 8000 @ mymaster 192.168.2.101 8000   
 
 
5.登录redis和sentinel再次确认切换后的主从关系