Redis集群是Redis分布式解决方案，解决了单机中心化的问题
一、理论基础
主要包括2部分：节点主从、哈希Slot（槽）
节点主从：
1、master可由有多个slaver，slaver可以有自己的slaver，主从关系手动指定，当master下线后slaver会自动升为master；
2、读写分离，master负责写以及数据同步给slaver，slaver负责读，slaver扩容提高读效率；
3、slaver获取master数据后压入磁盘，再load进内存，client端从内存中读取数据，当增加一个slaver，会主动通知master，master将全量数据发送给slaver，数据量大将影响性能；
优点：读写分离，增加slaver提交读的并发能力；
缺点：master写是瓶颈；
hash slot
1、对象保存前先进行CRC16哈希到指定slot(节点)；
2、每个节点分配一个slot段，slot不能缺失也不能重复；
3、node之间相互监听，一旦有node退出或加入，会按照slot为单位做数据迁移；
优点：每个node互相监听，高并发数据写入、读出，任务繁重；
优点：将写操作分摊到了多个节点，提高写并发，扩容简单；
节点主从 && 哈希slot
1、主从和hash相互弥补优缺点；
2、先hash分逻辑节点，每个节点内部主从；
3、扩展并发读添加slaver，扩展并发写添加master；
二、集群搭建
集群操作：
//集群(cluster)
CLUSTER INFO 打印集群的信息
CLUSTER NODES 列出集群当前已知的所有节点（node），以及这些节点的相关信息。
//节点(node)
CLUSTER MEET
CLUSTER FORGET
CLUSTER REPLICATE
CLUSTER SAVECONFIG 将节点的配置文件保存到硬盘里面。
//槽(slot)
CLUSTER ADDSLOTS
CLUSTER DELSLOTS
CLUSTER FLUSHSLOTS 移除指派给当前节点的所有槽，让当前节点变成一个没有指派任何槽的节点。
CLUSTER SETSLOT
CLUSTER SETSLOT
CLUSTER SETSLOT
CLUSTER SETSLOT
//键 (key)
CLUSTER KEYSLOT
CLUSTER COUNTKEYSINSLOT
CLUSTER GETKEYSINSLOT
1、安装redis镜像
yimaoqian@yimaoqian ~ docker pull redis
2、修改配置文件
下载redishttp://download.redis.io/releases/，解压后得到redis.conf，添加或修改如下配置：
bind 0.0.0.0
daemonize no
requirepass 123456
masterauth 123456
cluster-enabled yes
cluster-config-file nodes-6379.conf
cluster-node-timeout 15000
3、运行redis集群
使用6个redis节点，3主3从
docker run --privileged=true --name redis1 --net redis-net -p 6001:6379 -v $PWD/6001/conf/redis.conf:/data/config/redis.conf -v $PWD/6001/data:/data -d redis:latest redis-server /data/config/redis.conf --appendonly yes
docker run --privileged=true --name redis2 --net redis-net -p 6002:6379 -v $PWD/6002/conf/redis.conf:/data/config/redis.conf -v $PWD/6002/data:/data -d redis:latest redis-server /data/config/redis.conf --appendonly yes
docker run --privileged=true --name redis3 --net redis-net -p 6003:6379 -v $PWD/6003/conf/redis.conf:/data/config/redis.conf -v $PWD/6003/data:/data -d redis:latest redis-server /data/config/redis.conf --appendonly yes
docker run --privileged=true --name redis4 --net redis-net -p 6004:6379 -v $PWD/6004/conf/redis.conf:/data/config/redis.conf -v $PWD/6004/data:/data -d redis:latest redis-server /data/config/redis.conf --appendonly yes
docker run --privileged=true --name redis5 --net redis-net -p 6005:6379 -v $PWD/6005/conf/redis.conf:/data/config/redis.conf -v $PWD/6005/data:/data -d redis:latest redis-server /data/config/redis.conf --appendonly yes
docker run --privileged=true --name redis6 --net redis-net -p 6006:6379 -v $PWD/6006/conf/redis.conf:/data/config/redis.conf -v $PWD/6006/data:/data -d redis:latest redis-server /data/config/redis.conf --appendonly yes
4、查看容器状态
yimaoqian@yimaoqian ~ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
264773dfc76a redis:latest "docker-entrypoint.s…" 3 hours ago Up 3 hours 0.0.0.0:6006->6379/tcp redis6
cf017727c5e1 redis:latest "docker-entrypoint.s…" 3 hours ago Up 3 hours 0.0.0.0:6005->6379/tcp redis5
ab6041e6e5c2 redis:latest "docker-entrypoint.s…" 3 hours ago Up 3 hours 0.0.0.0:6004->6379/tcp redis4
8faeccf80150 redis:latest "docker-entrypoint.s…" 3 hours ago Up 3 hours 0.0.0.0:6003->6379/tcp redis3
bdb2a392c8c9 redis:latest "docker-entrypoint.s…" 3 hours ago Up 3 hours 0.0.0.0:6002->6379/tcp redis2
a986b0a1a4d8 redis:latest "docker-entrypoint.s…" 3 hours ago Up 37 minutes 0.0.0.0:6001->6379/tcp redis1
5、运行redis集群容器
查看容器IP：
yimaoqian@yimaoqian ~/wutong/specialGroup/redis docker inspect redis1 redis2 redis3 redis4 redis5 redis6|grep IPA
"SecondaryIPAddresses": null,
"IPAddress": "",
"IPAMConfig": null,
"IPAddress": "172.20.0.2",
"SecondaryIPAddresses": null,
"IPAddress": "",
"IPAMConfig": null,
"IPAddress": "172.20.0.3",
"SecondaryIPAddresses": null,
"IPAddress": "",
"IPAMConfig": null,
"IPAddress": "172.20.0.4",
"SecondaryIPAddresses": null,
"IPAddress": "",
"IPAMConfig": null,
"IPAddress": "172.20.0.5",
"SecondaryIPAddresses": null,
"IPAddress": "",
"IPAMConfig": null,
"IPAddress": "172.20.0.6",
"SecondaryIPAddresses": null,
"IPAddress": "",
"IPAMConfig": null,
"IPAddress": "172.20.0.7",
集群感知：
localhost:6001> CLUSTER MEET 172.20.0.3 6379
OK
localhost:6001> CLUSTER MEET 172.20.0.4 6379
OK
localhost:6001> CLUSTER MEET 172.20.0.5 6379
OK
localhost:6001> CLUSTER MEET 172.20.0.6 6379
OK
localhost:6001> CLUSTER MEET 172.20.0.7 6379
OK
localhost:6001> cluster nodes
a4cfac29113a66a278c37268d2ca49fb62873e93 172.20.0.7:6379@16379 master - 0 1572328475000 5 connected
e3316f5cdc75a7e7ea259c3b9a00dee4dc6afb4c 172.20.0.5:6379@16379 master - 0 1572328476000 3 connected
8a5363c38e406227ffcc89080edd4b84d0d22ba4 172.20.0.2:6379@16379 myself,master - 0 1572328474000 1 connected
a179d778c65c3caeeaca5f095fb4a1380453a07a 172.20.0.4:6379@16379 master - 0 1572328476510 2 connected
fdddf383f8bf53447926e5efb80a7405ec85294d 172.20.0.3:6379@16379 master - 0 1572328474495 0 connected
383bd17b9a8c3a64f664637dd7cdb764a17324b8 172.20.0.6:6379@16379 master - 0 1572328475000 4 connected
分配slot：
查看槽信息
localhost:6001> CLUSTER INFO
cluster_state:fail
cluster_slots_assigned:0 # 被分配槽的个数为0
cluster_slots_ok:0
cluster_slots_pfail:0
cluster_slots_fail:0
cluster_known_nodes:6
cluster_size:0
cluster_current_epoch:5
cluster_my_epoch:2
cluster_stats_messages_ping_sent:260418
cluster_stats_messages_pong_sent:260087
cluster_stats_messages_meet_sent:10
cluster_stats_messages_sent:520515
cluster_stats_messages_ping_received:260086
cluster_stats_messages_pong_received:260328
cluster_stats_messages_meet_received:1
cluster_stats_messages_received:520415
分配槽位：
#!/bin/bash
# node1 localhost:6001 172.20.0.2
n=0
for ((i=n;i<=5461;i++))
do
/usr/local/bin/redis-cli -h localhost -p 6001 -a 123456 CLUSTER ADDSLOTS $i
done
# node2 localhost:6002 172.20.0.3
n=5462
for ((i=n;i<=10922;i++))
do
/usr/local/bin/redis-cli -h localhost -p 6002 -a 123456 CLUSTER ADDSLOTS $i
done
# node3 localhost:6003 172.20.0.4
n=10923
for ((i=n;i<=16383;i++))
do
/usr/local/bin/redis-cli -h localhost -p 6003 -a 123456 CLUSTER ADDSLOTS $i
done
6、高可用
添加从节点：
#!/bin/bash
/usr/local/bin/redis-cli -h localhost -p 6004 -a 123456 CLUSTER REPLICATE 8a5363c38e406227ffcc89080edd4b84d0d22ba4
/usr/local/bin/redis-cli -h localhost -p 6005 -a 123456 CLUSTER REPLICATE fdddf383f8bf53447926e5efb80a7405ec85294d
/usr/local/bin/redis-cli -h localhost -p 6006 -a 123456 CLUSTER REPLICATE a179d778c65c3caeeaca5f095fb4a1380453a07a
1、备用节点不允许分配槽位；
2、在当前节点操作，将当前节点添加为node_id的副本节点；
3、从节点需要运行在cluster模式下，先添加到集群，再做复制；
查看节点信息：3主3从高可用
ocalhost:6004> cluster nodes
a4cfac29113a66a278c37268d2ca49fb62873e93 172.20.0.7:6379@16379 slave a179d778c65c3caeeaca5f095fb4a1380453a07a 0 1572332713422 5 connected
a179d778c65c3caeeaca5f095fb4a1380453a07a 172.20.0.4:6379@16379 master - 0 1572332714428 2 connected 10923-16383
fdddf383f8bf53447926e5efb80a7405ec85294d 172.20.0.3:6379@16379 master - 0 1572332712417 0 connected 5462-10922
383bd17b9a8c3a64f664637dd7cdb764a17324b8 172.20.0.6:6379@16379 slave fdddf383f8bf53447926e5efb80a7405ec85294d 0 1572332713000 4 connected
e3316f5cdc75a7e7ea259c3b9a00dee4dc6afb4c 172.20.0.5:6379@16379 myself,master - 0 1572332712000 6 connected 0-5461
8a5363c38e406227ffcc89080edd4b84d0d22ba4 172.20.0.2:6379@16379 slave e3316f5cdc75a7e7ea259c3b9a00dee4dc6afb4c 0 1572332712000 6 connected